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  <front>
    <title abbrev="Execution-Finality Protocol Layer">
      The Missing Protocol Layer for the Agentic Internet: Computation
      Is Not Authority
    </title>

    <seriesInfo name="Internet-Draft" value="draft-das-execution-finality-protocol-layer-01"/>

    <author initials="S." surname="Das" fullname="Sangam Das">
      <organization>Independent Inventor</organization>
      <address>
        <postal>
          <city>Balasore</city>
          <region>Odisha</region>
          <country>India</country>
        </postal>
        <email>info@sangamdas.com</email>
      </address>
    </author>

    <date year="2026" month="September" day="10"/>

    <area>General</area>
    <workgroup>Independent Submission</workgroup>

    <keyword>execution finality</keyword>
    <keyword>agentic AI</keyword>
    <keyword>candidate act</keyword>
    <keyword>authorization</keyword>
    <keyword>threat model</keyword>
    <keyword>finality sink</keyword>

    <abstract>
      <t>
        TLS tells you the channel is authentic.  OAuth tells you the caller
        holds a valid grant.  HTTPS tells you the origin is who it claims to
        be.  EMV tells you a payment cryptogram is transaction-specific.
        None of these mechanisms answer a question that autonomous,
        machine-speed systems now raise on every turn: is <em>this specific act</em>, generated by <em>this</em> model, agent, or workload, at <em>this</em> moment, actually authorized to become
        externally effective?
      </t>
      <t>
        Large language model agents, autonomous cloud workloads, and
        machine-to-machine network functions increasingly compute, decide,
        and act inside a single event loop, at latencies where no human,
        log reviewer, or downstream audit process can intervene before an
        API call fires, a payment settles, a file leaves the enterprise
        boundary, or a physical actuator moves.  Transport, authentication,
        and authorization protocols were designed for a world in which the
        gap between "this request was generated" and "this request had a
        chance to be reviewed" was measured in human-relevant time.  That
        gap has collapsed to milliseconds.  Existing protocol layers were
        never built to close it, because the question they answer --
        identity, channel integrity, delegated scope -- is a necessary but
        categorically different question from whether <em>this act, right now, should be allowed to leave
        computation and become consequence</em>.
      </t>
      <t>
        This document specifies an architectural pattern, execution
        finality, that treats every machine-generated operation as a
        Candidate Act held in a Non-Effective State until a Protected
        Enforcement Domain validates act-specific authority -- purpose,
        destination, jurisdiction, freshness, revocation state, policy
        epoch, and runtime integrity -- and issues a narrowly scoped,
        non-bearer Execution Handle bound to that act and to a specific
        Finality Sink, the first boundary at which the act would otherwise
        become externally effective.  The document formalizes the
        vocabulary, a cold-path/hot-path split for latency-sensitive
        deployment, a structured threat model with adversary-facing
        pseudocode, an incremental migration path for coexistence with
        TLS, HTTPS, OAuth, and EMV rather than replacement of them, and
        worked examples spanning AI agents, payments, telecommunications,
        cloud infrastructure, satellite command, industrial control, and
        robotics.
      </t>
      <t>
        The central claim is narrow and falsifiable: <em>computation does not itself confer authority for
        consequence</em>, and no general, cross-domain Internet layer
        currently makes that separation a structural property of the
        release path rather than an application-specific convention.  This
        document is intended to solicit IETF community review of whether
        that gap is real, whether it is already covered by existing or
        in-progress work, and if not, which venue should take it up.
      </t>
      <t>
        This document describes a patent-pending architectural concept.
        Any intellectual-property rights or disclosure obligations relating
        to implementation are outside the technical scope of this document
        and are subject to applicable IETF IPR procedures, including
        BCP&nbsp;79.
      </t>
    </abstract>

  </front>

  <middle>

    <section anchor="intro" title="Introduction">
      <t>
        The Internet was built in layers because different technical
        problems require different mechanisms.
      </t>
      <t>
        IP provides internetwork delivery.  Transport protocols carry data
        between endpoints.  TLS protects communication channels.  HTTP
        defines application-level request and response semantics.  HTTPS
        combines HTTP semantics with a secured connection to an
        authoritative origin.  Authentication systems establish identity.
        Authorization frameworks can delegate access.  Payment protocols
        provide payment-specific authentication and authorization
        mechanisms.  Logs and ledgers record events.
      </t>
      <t>
        These mechanisms solve indispensable problems.  This document does
        not propose replacing any of them.
      </t>
      <t>
        However, modern digital information increasingly represents
        commands rather than merely content, and the entity generating
        those commands is, with growing frequency, itself a model rather
        than a human operator sitting at a keyboard.
      </t>
      <t>
        An AI-generated message may invoke an API.  An API request may
        export a database.  An autonomous workload may initiate a payment.
        A network controller may reconfigure infrastructure.  A telecom
        function may trigger a transmission.  A satellite controller may
        issue an RF or command operation.  A machine-generated instruction
        may cause physical actuation.
      </t>
      <t>
        This creates a distinct architectural question:
      </t>
      <t>
        Even when the information is correctly transported,
        cryptographically protected, authenticated, and syntactically
        valid, should the represented act be allowed to become externally
        effective?
      </t>
      <t>
        This document calls the architectural control of that boundary
        execution finality.
      </t>
      <t>
        Readers seeking additional explanatory material, industry-specific
        examples, frequently asked questions, implementation discussion,
        and illustrative diagrams may consult the accompanying public
        technical disclosure:
      </t>
      <t>
        Sangam Das, "The Internet Solved Communication.  It Never Solved
        Authority," Zenodo, August 2026 <xref target="ZENODO-DAS"/>.
        <eref target="https://zenodo.org/records/22082995"/>
      </t>
      <t>
        The supplementary material provides broader discussion of
        execution finality across artificial intelligence,
        telecommunications and 5G/6G, cloud and data-centre infrastructure,
        payments, satellite systems, cybersecurity, industrial control,
        robotics, and other consequence-bearing environments.  It is
        provided for explanatory context; this Internet-Draft defines the
        architectural discussion independently.
      </t>
    </section>

    <section anchor="layers" title="The Internet Layers We Already Have">
      <t>A simplified view is:</t>
      <dl>
        <dt>IP / transport:</dt>
        <dd>How does information reach another endpoint?</dd>
        <dt>TLS:</dt>
        <dd>Can communicating peers establish a secure channel with
          authentication, confidentiality, and integrity?</dd>
        <dt>HTTP:</dt>
        <dd>How are application requests, responses, resources, methods,
          and representations expressed?</dd>
        <dt>HTTPS:</dt>
        <dd>Can HTTP communication with the intended origin be protected by
          an authenticated, confidential, integrity-protected channel?</dd>
        <dt>OAuth and related authorization frameworks:</dt>
        <dd>What access or delegated authority may a client receive?</dd>
        <dt>EMV technologies:</dt>
        <dd>Within the payment ecosystem, can payment credentials,
          transaction-specific data, cardholder or device information, and
          issuer authorization be used to determine whether a payment
          transaction should proceed?</dd>
        <dt>Logs / ledgers:</dt>
        <dd>What happened, and in what sequence?</dd>
      </dl>
      <t>These questions are not replaced by execution finality.</t>
      <t>The additional question is:</t>
      <t>
        May this specific consequential machine act become externally
        effective at this particular boundary, under the current protected
        authorization state?
      </t>
    </section>

    <section anchor="missing-q" title="The Missing Architectural Question">
      <t>
        Many systems couple the ability to compute an operation with the
        practical ability to execute it.
      </t>
      <t>
        A workload may obtain an authenticated session, an API credential,
        a delegated token, and a network route, and then possess all of the
        technical machinery required to produce the external effect.
      </t>
      <t>
        Application-specific controls can and do authorize individual
        actions.  Payment systems can authorize transactions.  Network
        devices can enforce policy.  Operating systems can mediate
        privileged operations.
      </t>
      <t>
        The claim of this document is therefore not that existing systems
        never authorize actions.
      </t>
      <t>
        The narrower architectural observation is that there is no general
        cross-domain layer whose central invariant is: protected
        act-specific validation MUST remain a dependency of the
        consequence-bearing release path itself.
      </t>
      <t>Execution finality separates:</t>
      <t>authority to compute or prepare an act;</t>
      <t>from:</t>
      <t>authority to make that act externally effective.</t>
    </section>

    <section anchor="agentic-era" title="Why Machine Time Changes the Problem: The Agentic Era">
      <t>
        Earlier digital systems frequently operated within workflows where
        human review, incident response, rollback, revocation, or manual
        intervention remained relevant to the time scale of the action.
      </t>
      <t>
        AI-native infrastructure compresses that interval to the point
        where it no longer functions as a safety margin.  This is the
        specific condition that motivates this document, and it is worth
        stating plainly: the reason execution finality did not need to
        exist as a general cross-domain layer in 1995, 2005, or even 2015
        is that the actor generating consequential requests was, in the
        overwhelming majority of cases, a human, and humans are slow enough
        relative to review, monitoring, and manual intervention that
        application-level and post-hoc controls were sufficient.
      </t>
      <t>
        Autonomous agents can invoke tools, call APIs, transmit data,
        create files, modify databases, initiate payments, trigger
        workflows, reconfigure infrastructure, generate
        telecommunications operations, or issue machine commands within
        milliseconds, in loops that may run thousands of times per hour
        without a human observing any individual iteration.  An agent
        does not need to be malicious to be dangerous in this model: a
        correctly authenticated, correctly authorized, non-adversarial
        agent that is simply wrong about the current purpose, destination,
        or policy state can still generate a fully valid, fully
        transportable, fully credentialed Candidate Act that should not
        become effective.
      </t>
      <t>
        By the time a log is read:
      </t>
      <ul>
        <li>the data may already have crossed a jurisdiction;</li>
        <li>the payment may already have been released;</li>
        <li>the network state may already have changed;</li>
        <li>the telecom transmission may already have occurred;</li>
        <li>the model or system memory may already have changed; or</li>
        <li>the physical actuation may already have happened.</li>
      </ul>
      <t>Post-event evidence is essential.</t>
      <t>But: evidence of an unauthorized act is not prevention of the act.</t>
      <t>
        AI-native infrastructure therefore increases the importance of
        pre-effectuation authorization, and does so specifically because
        the traditional backstop -- a human somewhere in the loop who is
        slow enough to be a safety margin -- is being architecturally
        removed by the same agentic systems that make this document
        relevant.
      </t>
    </section>

    <section anchor="architecture" title="Execution-Finality Architecture">
      <t>
        The proposed architecture introduces an execution-finality layer
        between computation and externally effective consequence.
      </t>
      <t>A conceptual sequence is:</t>
      <ol type="1">
        <li>A workload computes or prepares an operation.</li>
        <li>The operation is represented as a Candidate Act.</li>
        <li>The Candidate Act is placed or maintained in a Non-Effective
          State.</li>
        <li>A Protected Enforcement Domain or equivalent protected
          mechanism validates the required authority and protected
          state.</li>
        <li>Successful validation produces or resolves protected
          validation evidence and narrowly scoped effectuation
          authority.</li>
        <li>The authority is bound to the intended Candidate Act, scope,
          destination, protected state, and Finality Sink.</li>
        <li>The Finality Sink independently verifies the required
          authority.</li>
        <li>Only after successful verification may the protected external
          effect occur.</li>
      </ol>
      <t>Failure to validate leaves the Candidate Act non-effective.</t>
    </section>

    <section anchor="candidate-act" title="Candidate Acts and the Non-Effective State">
      <t>
        A Candidate Act is a proposed operation capable of producing an
        external consequence but not yet permitted to do so.
      </t>
      <t>Candidate Acts may include:</t>
      <ul>
        <li>AI-agent tool calls;</li>
        <li>API requests;</li>
        <li>file or database exports;</li>
        <li>storage writes;</li>
        <li>model-memory updates;</li>
        <li>payment instructions;</li>
        <li>telecom transmissions;</li>
        <li>network configuration changes;</li>
        <li>radio emissions;</li>
        <li>satellite commands;</li>
        <li>content publication;</li>
        <li>notification rendering;</li>
        <li>actuator commands;</li>
        <li>vehicle or robotic operations; and</li>
        <li>other consequence-bearing machine operations.</li>
      </ul>
      <t>
        The Non-Effective State is the logical state in which the
        Candidate Act may exist computationally but cannot yet cross the
        relevant effectuation boundary.
      </t>
      <t>In shorthand: computation exists != consequence is authorized</t>
    </section>

    <section anchor="validation" title="Protected Validation and Bounded Authority">
      <t>
        Before effectuation, applicable conditions may be validated inside
        a protected hardware, cryptographically isolated, or otherwise
        protected enforcement environment.
      </t>
      <t>Conditions may include:</t>
      <ul>
        <li>actor identity;</li>
        <li>workload identity;</li>
        <li>AI-agent identity;</li>
        <li>purpose;</li>
        <li>user or enterprise authority;</li>
        <li>consent;</li>
        <li>destination;</li>
        <li>recipient;</li>
        <li>jurisdiction;</li>
        <li>policy epoch;</li>
        <li>revocation state;</li>
        <li>nonce or freshness state;</li>
        <li>quota;</li>
        <li>permitted effect;</li>
        <li>runtime integrity;</li>
        <li>protected state;</li>
        <li>algorithm or model identity;</li>
        <li>execution context; and</li>
        <li>Finality Sink identity.</li>
      </ul>
      <t>
        Successful validation may produce protected evidence and a bounded
        Execution Handle or equivalent capability.
      </t>
      <t>
        Such effectuation authority may be non-bearer, single-use,
        quota-limited, revocable, time-bounded, purpose-bound,
        destination-bound, state-bound, and Finality-Sink-bound.
      </t>
      <t>
        Possession or copying of a representation alone should not
        transfer the underlying execution authority to another actor,
        context, destination, session, or sink.
      </t>
    </section>

    <section anchor="sink" title="The Finality Sink">
      <t>
        The Finality Sink is the first boundary at which a Candidate Act
        would become externally effective.
      </t>
      <t>
        It is a functional role and does not require one specific physical
        component.
      </t>
      <t>A Finality Sink may be:</t>
      <ul>
        <li>an API dispatcher;</li>
        <li>an egress gateway;</li>
        <li>a model-output emitter;</li>
        <li>a telecom gateway;</li>
        <li>an IMS or network-function boundary;</li>
        <li>a radio transmission chain;</li>
        <li>a SmartNIC or DPU;</li>
        <li>a memory controller;</li>
        <li>a storage writer;</li>
        <li>a payment-release interface;</li>
        <li>a settlement or ledger bridge;</li>
        <li>an operating-system broker;</li>
        <li>a notification renderer;</li>
        <li>a satellite-command interface; or</li>
        <li>a physical actuator.</li>
      </ul>
      <t>
        The Finality Sink verifies the applicable effectuation authority
        before releasing the consequence-bearing operation.
      </t>
      <t>If verification fails: the Candidate Act remains non-effective.</t>
      <t>
        If verification succeeds: effectuation may proceed only within the
        verified scope.
      </t>
      <t>
        Where required, single-use capability or protected state is
        consumed before or atomically with effectuation.
      </t>
    </section>

    <section anchor="comparison" title="Comparison with TLS, HTTPS, OAuth, EMV, and Ledgers">

      <section anchor="cmp-tls" title="TLS">
        <t>
          TLS 1.3 <xref target="TLS13"/> is designed to provide a secure channel between
          communicating peers.  Its security properties include peer
          authentication, confidentiality, integrity, and record-layer
          protections.
        </t>
        <t>TLS therefore answers questions such as:</t>
        <t>Is this the authenticated peer?</t>
        <t>
          Has the communication been protected from eavesdropping or
          undetected modification?
        </t>
        <t>
          TLS does not define the application-specific semantic rule that
          a consequential command carried inside the protected channel is
          authorized to produce a particular external effect.
        </t>
        <t>
          A malicious, compromised, or over-authorized endpoint can
          therefore transmit a perfectly valid TLS-protected command.
        </t>
        <t>
          Execution finality is intended to operate after or alongside
          secure transport by independently controlling release of the
          consequential effect.
        </t>
      </section>

      <section anchor="cmp-https" title="HTTPS">
        <t>
          HTTPS combines HTTP <xref target="HTTP"/> semantics with a secured connection to an
          authoritative origin.  HTTP request methods convey client
          intentions regarding identified resources, while HTTPS provides
          authentication of the relevant origin and confidentiality and
          integrity protection for the HTTP exchange.
        </t>
        <t>This is an important distinction: HTTPS is not merely encryption.</t>
        <t>
          Nevertheless, successful HTTPS communication does not itself
          establish a universal rule that every downstream real-world
          effect requested in the HTTP message is authorized for its
          current purpose, jurisdiction, protected state, runtime
          condition, and effectuation boundary.
        </t>
        <t>An application can implement such controls, but they are application-specific.</t>
        <t>
          Execution finality proposes making the final act-level release
          dependency explicit and reusable across domains.
        </t>
      </section>

      <section anchor="cmp-oauth" title="OAuth and Delegated Authorization">
        <t>
          OAuth and similar systems can provide powerful delegated
          authorization and scope-limited access.
        </t>
        <t>
          These mechanisms may already be used to prevent unauthorized API
          operations.
        </t>
        <t>Execution finality does not claim otherwise.</t>
        <t>
          The distinction is that access authorization and effectuation
          authority need not be identical.
        </t>
        <t>
          A token may authorize access to an API or resource while a
          particular requested consequence may require additional
          validation of purpose, current state, destination, jurisdiction,
          freshness, revocation, act-specific attributes, and the identity
          of the actual effectuation boundary.
        </t>
        <t>
          The execution-finality model places that last validation
          structurally at or immediately before the Finality Sink.
        </t>
      </section>

      <section anchor="cmp-emv" title="EMV">
        <t>
          EMV must be distinguished carefully because it already contains
          transaction-specific security and authorization mechanisms.
        </t>
        <t>
          EMV Chip <xref target="EMV-CHIP"/> can generate transaction-specific cryptograms.
          Depending on the transaction flow, cryptographic information can
          be verified locally by a terminal or remotely by an issuer.  EMV
          3-D Secure <xref target="EMV-3DS"/> also supports payment authentication and issuer
          decision-making for e-commerce transactions.
        </t>
        <t>EMV therefore demonstrates an important principle:</t>
        <t>
          high-throughput infrastructure can make transaction-specific
          cryptographic authorization part of a real-time
          consequence-bearing workflow.
        </t>
        <t>
          Execution finality does NOT claim that EMV merely authenticates
          a generic credential or that EMV fails to authorize payment
          transactions.
        </t>
        <t>The distinction proposed here is scope and architectural generality.</t>
        <t>EMV is purpose-built for payment ecosystems and payment consequences.</t>
        <t>
          Execution finality proposes a generalized abstraction for
          arbitrary machine-generated consequences, including AI-agent
          tool use, data export, telecom transmission, cloud and storage
          operations, network reconfiguration, satellite commands, and
          physical actuation.
        </t>
        <t>It additionally emphasizes a common cross-domain structure:</t>
        <artwork><![CDATA[
Candidate Act
    ->
Non-Effective State
    ->
Protected Validation
    ->
narrowly scoped non-bearer effectuation authority
    ->
Finality-Sink verification
    ->
external effect
        ]]></artwork>
        <t>
          EMV is therefore better understood as a useful domain-specific
          analogy showing the feasibility and value of transaction-bound
          authorization, rather than as a protocol that the proposed
          architecture seeks to replace.
        </t>
      </section>

      <section anchor="cmp-ledgers" title="Logs and Distributed Ledgers">
        <t>
          Logs, audit systems, and ledgers can provide evidence, ordering,
          integrity protection, or consensus regarding events.
        </t>
        <t>They can also participate in authorization architectures.</t>
        <t>
          However, recording an event does not by itself prove that the
          event was authorized to become externally effective before it
          occurred.
        </t>
        <t>
          Execution finality can use a ledger or validation receipt where
          useful, but a ledger is not a baseline requirement.
        </t>
      </section>

      <section anchor="cmp-summary" title="Summary">
        <table>
          <thead>
            <tr>
              <th>Mechanism</th>
              <th>Primary property</th>
            </tr>
          </thead>
          <tbody>
            <tr><td>IP/Transport</td><td>Information delivery</td></tr>
            <tr><td>TLS</td><td>Secure authenticated channel</td></tr>
            <tr><td>HTTP</td><td>Request/response and resource semantics</td></tr>
            <tr><td>HTTPS</td><td>HTTP over a secured authoritative-origin channel</td></tr>
            <tr><td>OAuth</td><td>Delegated access authorization</td></tr>
            <tr><td>EMV</td><td>Payment-domain transaction authentication and authorization</td></tr>
            <tr><td>Logs/Ledgers</td><td>Evidence, ordering, recording, or consensus</td></tr>
            <tr><td>Execution Finality</td><td>Protected act-specific authorization remains a prerequisite of external effectuation at the consequence boundary</td></tr>
          </tbody>
        </table>
      </section>

    </section>

    <section anchor="latency" title="Latency, Deployment Feasibility, and the Cold/Hot Path">
      <t>
        Execution-finality control is useful only if it can be implemented
        without placing expensive policy reasoning into every
        latency-sensitive operation.  A practical implementation therefore
        divides processing into a cold path and a hot path, and this
        section expands the split into concrete per-domain latency
        budgets, a failure taxonomy for the hot path, and pseudocode for
        both paths.
      </t>

      <section anchor="latency-cold" title="Cold Path">
        <t>The cold path may perform:</t>
        <ul>
          <li>policy evaluation;</li>
          <li>AI risk assessment;</li>
          <li>authorization issuance;</li>
          <li>consent processing;</li>
          <li>jurisdiction determination;</li>
          <li>credential validation;</li>
          <li>workload or model assessment;</li>
          <li>destination approval;</li>
          <li>key provisioning;</li>
          <li>rule compilation;</li>
          <li>protected-state preparation; and</li>
          <li>creation of validation evidence.</li>
        </ul>
        <t>
          The cold path is not latency-bounded by the effectuation event.
          It runs ahead of, or asynchronously with, the act it will
          eventually authorize, and its output is a compact, independently
          verifiable artifact (the Execution Handle plus validation
          evidence) rather than a live policy decision the hot path must
          wait on.
        </t>
      </section>

      <section anchor="latency-hot" title="Hot Path">
        <t>The effectuation-time hot path may be restricted to operations such as:</t>
        <ul>
          <li>identifying the Candidate Act;</li>
          <li>checking or reconstructing an act digest;</li>
          <li>verifying a signature, MAC, attestation, or protected record;</li>
          <li>checking nonce or freshness state;</li>
          <li>checking revocation or policy epoch;</li>
          <li>checking scope;</li>
          <li>checking Finality-Sink binding;</li>
          <li>consuming single-use or quota state; and</li>
          <li>releasing or denying the consequence-bearing resource.</li>
        </ul>
        <t>
          Every hot-path operation above is a bounded, deterministic,
          local check.  None of them requires a network round trip to a
          policy engine, a human reviewer, or an AI model.  This is the
          property that makes the architecture compatible with
          microsecond-to-low-millisecond release paths: the reasoning that
          is genuinely expensive (what should be allowed, for whom, under
          what conditions) has already happened on the cold path, and the
          hot path only checks whether the artifact produced by that
          reasoning still applies to the exact act now in front of the
          sink.
        </t>
      </section>

      <section anchor="latency-budgets" title="Indicative Per-Domain Latency Budgets">
        <t>
          The following budgets are illustrative, not normative, and are
          intended only to show that hot-path verification is compatible
          with the timing constraints of the domains discussed in <xref
          target="industry"/>.  Actual figures depend on hardware,
          cryptographic primitive, assurance level, and topology, and this
          document makes no universal latency claim.
        </t>
        <table>
          <thead>
            <tr><th>Domain</th><th>Typical release-path budget</th><th>Hot-path fit</th></tr>
          </thead>
          <tbody>
            <tr><td>API/tool-call dispatch (agentic AI)</td><td>1-50 ms</td><td>Local signature/MAC check, cached revocation epoch</td></tr>
            <tr><td>5G/6G user-plane gateway action</td><td>&lt;1-10 ms</td><td>Hardware-assisted verification, precomputed epoch table</td></tr>
            <tr><td>Card-present/EMV-adjacent payment release</td><td>~100-300 ms (existing EMV budget)</td><td>Composable with existing terminal/issuer round trip</td></tr>
            <tr><td>Industrial/safety actuator command</td><td>&lt;10 ms (interlock-class)</td><td>Local protected-state check only; no remote call in hot path</td></tr>
            <tr><td>Satellite command uplink</td><td>Seconds (propagation-bound)</td><td>Verification cost negligible relative to propagation delay</td></tr>
          </tbody>
        </table>
      </section>

      <section anchor="latency-feasibility" title="Feasibility">
        <t>
          The architecture does not require a human reviewer, AI model,
          remote policy service, regulator, or distributed consensus
          protocol to execute synchronously for every Finality-Sink
          decision.
        </t>
        <t>
          Policy and authorization can be prepared on the cold path and
          transformed into compact locally verifiable evidence.
        </t>
        <t>The hot path can use mechanisms such as:</t>
        <ul>
          <li>public-key signature verification;</li>
          <li>MAC verification;</li>
          <li>HSM-backed protected state;</li>
          <li>TEE or secure-enclave state;</li>
          <li>monotonic counters;</li>
          <li>nonce stores;</li>
          <li>protected database transactions;</li>
          <li>cached revocation epochs;</li>
          <li>precomputed authorization artifacts; and</li>
          <li>device- or sink-bound credentials.</li>
        </ul>
        <t>
          This document therefore does not claim a universal latency
          number.  The architectural requirement is that expensive
          reasoning may remain outside the hot path while the final
          release decision remains independently enforceable at the
          consequence boundary.
        </t>
      </section>
    </section>

    <section anchor="legacy" title="Legacy System Interoperability and Incremental Migration">
      <t>
        A cross-domain architectural proposal is only deployable if it can
        be introduced without a forklift replacement of TLS, HTTPS, OAuth,
        EMV, or the applications built on them.  This section describes
        execution finality as an additive control plane, the specific
        interoperability points with each legacy mechanism, a
        gateway/shim deployment pattern for brownfield environments, and
        an explicit compatibility and downgrade posture.
      </t>

      <section anchor="legacy-principle" title="Additive, Not Substitutive">
        <t>
          Execution finality is designed to sit at or immediately before
          the existing release point of a legacy mechanism, not to replace
          the mechanism's channel security or its existing authorization
          semantics.  A Finality Sink can be implemented as a thin
          verification shim placed directly in front of an existing
          egress gateway, API dispatcher, or payment-release interface,
          without modifying the transport (TLS remains TLS), the
          application protocol (HTTP remains HTTP), or the existing
          delegated-authorization layer (OAuth tokens continue to be
          validated exactly as before).
        </t>
        <t>
          The added dependency is narrow: the shim additionally requires a
          valid, act-specific Execution Handle before forwarding the
          request to the legacy release path.  If no Execution Handle is
          required by local policy for a given operation class, the shim
          is a no-op and legacy behavior is unchanged.  This allows
          execution finality to be adopted operation-by-operation,
          starting with the highest-consequence acts (bulk data export,
          high-value payments, safety-critical actuation) and expanding
          coverage over time.
        </t>
      </section>

      <section anchor="legacy-tls" title="Interoperability with TLS/HTTPS">
        <t>
          No change to the TLS handshake, cipher suite negotiation, or
          certificate validation is required.  The Candidate Act, its
          digest, and the resulting Execution Handle can be carried as an
          application-layer artifact inside the existing HTTPS request
          (for example, as an additional header or a signed structured
          field), so that legacy HTTPS clients that do not generate an
          Execution Handle simply have the field absent, and a
          Finality-Sink shim in strict mode denies the act while a shim in
          permissive/observe mode logs the gap without blocking, which is
          the recommended posture during a migration window.
        </t>
      </section>

      <section anchor="legacy-oauth" title="Interoperability with OAuth">
        <t>
          Existing OAuth access tokens continue to gate resource access
          exactly as they do today.  The Execution Handle is a second,
          narrower artifact layered on top of, not instead of, the OAuth
          grant: an OAuth token can authorize a client to call an export
          API at all, while the Execution Handle additionally authorizes
          this specific export, to this destination, under the current
          policy epoch.  A resource server can be upgraded incrementally
          by adding an Execution-Handle check after its existing
          token-introspection step, with no change to the authorization
          server, token format, or grant flow.
        </t>
      </section>

      <section anchor="legacy-emv" title="Interoperability with EMV and Payment Rails">
        <t>
          Execution finality does not attempt to sit inside the EMV
          cryptogram computation or the issuer authorization step; that
          domain-specific, already-mature control is left intact.  Instead,
          an enterprise, agent-facing, or API-facing payment initiator can
          require an Execution Handle as a precondition to constructing
          the payment instruction that is handed to the existing
          EMV/payment-rail path, so the two controls compose in sequence
          (execution-finality check, then existing payment-domain
          authorization) rather than one subsuming the other.
        </t>
      </section>

      <section anchor="legacy-gateway" title="Gateway/Shim Deployment Pattern">
        <t>
          For brownfield environments where modifying every legacy
          endpoint is impractical, a Finality-Sink function can be
          deployed as a reverse proxy, service-mesh sidecar, API gateway
          plugin, or network-function filter placed in front of the
          unmodified legacy system.  This concentrates the hot-path check
          at a small number of well-known chokepoints instead of requiring
          every downstream service to be individually upgraded, and mirrors
          how WAFs, API gateways, and service meshes already retrofit
          authentication and rate-limiting onto legacy backends without
          modifying them.
        </t>
      </section>

      <section anchor="legacy-downgrade" title="Downgrade and Fallback Posture">
        <t>
          Three explicit deployment modes are RECOMMENDED for a migration
          window:
        </t>
        <dl>
          <dt>Observe mode:</dt>
          <dd>the shim evaluates Execution-Handle presence and validity
            but never blocks; results are logged for coverage
            measurement.</dd>
          <dt>Permissive mode:</dt>
          <dd>acts without a valid Execution Handle are allowed but
            flagged, while acts that present an invalid or expired handle
            are denied; this catches active misuse while legacy callers
            are migrated.</dd>
          <dt>Strict mode:</dt>
          <dd>a valid, act-specific Execution Handle is a hard
            precondition for release; this is the target end state for
            high-consequence operation classes.</dd>
        </dl>
        <t>
          A deployment SHOULD NOT silently fail open from strict mode to
          permissive or observe mode; any mode transition should be an
          explicit, auditable configuration change, since a silent
          downgrade under load or during an incident is itself a
          bypass path (see <xref target="threat-downgrade"/>).
        </t>
      </section>
    </section>

    <section anchor="workflow" title="Detailed Workflow, Pseudocode, and Examples">

      <section anchor="workflow-sequence" title="End-to-End Execution-Finality Workflow">
        <t>
          The following sequence is a non-limiting reference workflow.
          The components may be distributed across a device, operating
          system, network function, cloud service, protected hardware
          environment, payment system, enterprise gateway, or
          cyber-physical controller.
        </t>
        <t><strong>Step 1 - Compute or Receive a Proposed Operation.</strong>
          An ordinary compute environment, including an AI agent,
          application, cloud workload, network function, payment process,
          or controller, computes, receives, or prepares an operation.
          At this stage the operation has no independent authority to
          become externally effective merely because it was generated by
          an authenticated process or arrived over a secure channel.</t>
        <t><strong>Step 2 - Construct the Candidate Act.</strong>
          The system represents the proposed operation as a Candidate Act,
          which may include or reference: an act identifier; an operation
          type; canonicalized load-bearing act attributes; an actor,
          workload, or AI-agent identity; purpose and requested scope;
          source and destination; requested effect; jurisdictional
          context; session or transaction context; freshness information;
          a policy epoch; a revocation epoch; the intended Finality Sink;
          and a digest over the attributes that must remain invariant
          before effectuation.</t>
        <t><strong>Step 3 - Enter the Non-Effective State.</strong>
          The Candidate Act is placed or maintained in a Non-Effective
          State.  Computation may continue and validation may occur, but
          the consequence-bearing resource is withheld -- network egress,
          an API dispatch, a payment release, a database commit, a storage
          write, a message or notification release, a radio transmission,
          a satellite command, a model-output publication, a device wake,
          or a physical actuator transition.</t>
        <t><strong>Step 4 - Resolve the Applicable Authorization Context.</strong>
          The system resolves the authority required for this particular
          act, constraining permitted actor, purpose, destination, effect,
          data or resource scope, jurisdiction, time window, nonce or
          freshness state, quota, runtime identity, policy epoch,
          revocation state, and permitted Finality Sink.</t>
        <t><strong>Step 5 - Protected Validation.</strong>
          A Protected Enforcement Domain, or cooperating protected
          verifier, validates the Candidate Act against the required
          authorization context.  Validation failure does not produce
          effectuation authority.</t>
        <t><strong>Step 6 - Commit Protected Validation Evidence.</strong>
          If validation succeeds, the protected domain may commit
          validation evidence -- a signed receipt, protected state
          transition, authenticated record, hash-bound record, attested
          state, append-only event, ledger commitment, or equivalent --
          before or atomically with issuance of effectuation authority.</t>
        <t><strong>Step 7 - Issue or Resolve Scoped Non-Bearer Authority.</strong>
          After successful validation, the protected domain issues or
          resolves a narrowly scoped Execution Handle, bounded to the
          minimum required effect and bound to Candidate-Act digest,
          actor/workload, purpose, destination, jurisdiction, validity
          window, nonce, quota, policy epoch, revocation epoch, validation
          evidence, protected state, and Finality Sink.  The authority is
          non-bearer: possession or copying of its representation alone
          does not authorize another actor, context, destination, or sink
          to use it.</t>
        <t><strong>Step 8 - Present or Resolve Authority at the Finality Sink.</strong>
          The Candidate Act reaches the Finality Sink only as a still
          non-effective operation.  The Finality Sink, or a verifier
          structurally coupled to it, verifies the effectuation authority
          before release, including that the requested effect still
          matches the authorized act and that the authority has not
          expired, been revoked, been consumed, or been substituted across
          another sink or context.</t>
        <t><strong>Step 9 - Reconstruct or Recheck the Candidate Act.</strong>
          Where required, the Finality Sink reconstructs the load-bearing
          Candidate-Act attributes from sink-visible state and recomputes
          the act digest, preventing a validated act from being replaced
          with a different destination, amount, command, resource,
          recipient, output, or effect after validation.</t>
        <t><strong>Step 10 - Atomic Consumption and Effectuation.</strong>
          If all checks succeed, single-use or quota state is consumed
          before or atomically with release of the consequence-bearing
          resource, and effectuation occurs only within the verified
          scope.</t>
        <t><strong>Step 11 - Fail-Closed Denial.</strong>
          If any required condition is absent, invalid, stale, mismatched,
          replayed, revoked, quota-exhausted, or unverifiable, the
          Candidate Act remains non-effective.  Application intent,
          network delivery, authenticated identity, possession of a token,
          or prior approval are not treated as a substitute for successful
          Finality-Sink verification.</t>
        <t><strong>Step 12 - Optional Audit and Accountability.</strong>
          The system may record the allow or deny result for audit,
          dispute resolution, security analysis, incident response, or
          compliance.  Audit is complementary to execution finality: the
          protected consequence is controlled before release, and the
          audit record does not substitute for that control.</t>
      </section>

      <section anchor="workflow-pseudocode" title="Non-Limiting Pseudocode">
        <t>
          The following pseudocode illustrates the logical dependency.  It
          does not prescribe a wire format, cryptographic primitive,
          hardware technology, or deployment topology.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
CandidateAct {
    act_id
    actor_id
    operation_type
    purpose
    resource_scope
    destination
    jurisdiction
    requested_effect
    policy_epoch
    revocation_epoch
    freshness
    finality_sink_id
    canonical_act_digest
}

ExecutionAuthority {
    authority_id
    candidate_act_digest
    permitted_actor
    permitted_purpose
    permitted_scope
    permitted_destination
    permitted_effect
    permitted_jurisdiction
    expiry
    nonce_or_counter
    quota
    policy_epoch
    revocation_epoch
    validation_evidence_ref
    finality_sink_id
    non_bearer = true
}

process_candidate(candidate):

    candidate.state = NON_EFFECTIVE

    context = resolve_authorization_context(candidate)

    if context is absent:
        return DENY

    result = protected_validate(candidate, context)

    if result != VALID:
        return DENY

    evidence = commit_validation_evidence(
        candidate,
        context,
        result
    )

    authority = issue_scoped_authority(
        candidate,
        context,
        evidence
    )

    return deliver_non_effective_candidate_to_sink(
        candidate,
        authority
    )


finality_sink_receive(candidate, authority, sink_state):

    if candidate.state != NON_EFFECTIVE:
        return DENY

    if authority.finality_sink_id != sink_state.sink_id:
        return DENY

    if authority is expired or revoked:
        return DENY

    if authority.nonce_or_counter is already consumed:
        return DENY

    if authority.quota is exhausted:
        return DENY

    if authority.policy_epoch != sink_state.policy_epoch:
        return DENY

    if authority.revocation_epoch != sink_state.revocation_epoch:
        return DENY

    reconstructed_digest =
        canonical_digest(candidate.load_bearing_attributes)

    if reconstructed_digest !=
       authority.candidate_act_digest:
        return DENY

    if not scope_matches(candidate, authority):
        return DENY

    if not verify_validation_evidence(authority):
        return DENY

    atomic {
        consume(authority.nonce_or_counter)
        decrement_if_required(authority.quota)
        mark_effectuation_committed(candidate.act_id)

        release_only_authorized_effect(
            candidate,
            authority.permitted_effect
        )
    }

    return EFFECTUATED
        ]]></sourcecode>
      </section>

      <section anchor="wf-ai" title="AI-Agent Tool Invocation">
        <t>
          An AI agent prepares an instruction to export customer records
          to an external analysis service.
        </t>
        <t>Candidate Act: the proposed export, including dataset, fields,
          purpose, recipient, destination, model or agent identity, and
          requested transfer.</t>
        <t>Protected validation: verifies that the agent is permitted to
          perform the requested purpose, that the data scope is allowed,
          that the destination and jurisdiction are permitted, that policy
          and revocation state are current, and that the requested effect
          matches enterprise policy.</t>
        <t>Finality Sink: the first egress gateway, API dispatcher,
          storage-export boundary, or equivalent component capable of
          releasing the protected data.</t>
        <t>Result: a valid HTTPS session or OAuth token alone does not
          release the export.  The egress Finality Sink additionally
          requires valid act-specific effectuation authority.</t>
      </section>

      <section anchor="wf-payment" title="Payment and Settlement">
        <t>
          An AI agent, user application, enterprise workflow, or payment
          service prepares a payment instruction.
        </t>
        <t>Candidate Act: the proposed transfer, including amount, payer,
          payee, purpose, currency or asset, destination, transaction
          context, and requested payment effect.</t>
        <t>Protected validation: may combine existing payment-domain
          authorization with additional enterprise, agent, purpose, fraud,
          jurisdiction, quota, policy, or workflow constraints.</t>
        <t>Finality Sink: the component that first releases the payment
          into an irrevocable or externally consequential settlement
          path.</t>
        <t>Result: execution finality does not replace EMV or payment
          authorization.  It provides a generalized control point for
          binding a machine-generated payment act to additional protected
          constraints before release.</t>
      </section>

      <section anchor="wf-telecom" title="Telecommunications and 5G/6G">
        <t>
          An AI controller, network function, application, autonomous
          service, or machine-to-machine workflow prepares a consequential
          network operation.
        </t>
        <t>Candidate Act: a packet egress request, network-slice change,
          roaming operation, radio command, message release, gateway
          action, or satellite/NTN transmission.</t>
        <t>Protected validation: may verify network authority, purpose,
          subscriber or enterprise scope, destination, radio or spectrum
          constraints, jurisdiction, policy epoch, freshness, quota, and
          network-function identity.</t>
        <t>Finality Sink: a gateway, user-plane or control-plane
          enforcement point, radio chain, network-function boundary,
          satellite gateway, or other release boundary.</t>
        <t>Result: the fact that the request was generated by an
          authenticated network function does not alone make the requested
          consequence final.</t>
      </section>

      <section anchor="wf-cloud" title="Cloud and Data-Centre Infrastructure">
        <t>A workload prepares a storage, memory, DMA, accelerator, or network operation.</t>
        <t>Candidate Act: a DMA transfer, persistent storage write,
          accelerator-to-host transfer, privileged memory update,
          SmartNIC/DPU operation, or cloud egress event.</t>
        <t>Protected validation: may bind tenant, workload, purpose,
          resource range, destination, device identity, attested runtime,
          policy epoch, and revocation state.</t>
        <t>Finality Sink: a memory controller, storage controller,
          SmartNIC, DPU, accelerator boundary, hypervisor-mediated release
          point, or protected egress gateway.</t>
        <t>Result: compromise of the ordinary workload need not
          automatically imply authority to create every external or
          persistent effect available to the underlying infrastructure.</t>
      </section>

      <section anchor="wf-sat" title="Satellite and Non-Terrestrial Networks">
        <t>
          A ground system, autonomous controller, AI system, or network
          service prepares an RF, routing, payload, or satellite-control
          operation.
        </t>
        <t>Candidate Act: a beam command, RF transmission, payload
          instruction, routing update, cross-link operation, or spacecraft
          command.</t>
        <t>Protected validation: may verify mission authority, command
          type, destination, spacecraft identity, geographic or
          jurisdictional constraints, time window, operational state,
          freshness, policy epoch, and command scope.</t>
        <t>Finality Sink: the command-uplink interface, RF chain,
          payload-control boundary, or protected spacecraft actuator
          interface.</t>
        <t>Result: command generation and command effectuation remain
          separate authorities.</t>
      </section>

      <section anchor="wf-ics" title="Critical Infrastructure and Industrial Control">
        <t>An AI system or control application computes a command affecting a physical process.</t>
        <t>Candidate Act: a valve movement, breaker operation,
          process-setpoint change, robotic command, energy-grid action, or
          safety-system update.</t>
        <t>Protected validation: may verify operator or machine authority,
          permitted operating envelope, plant state, purpose, interlocks,
          freshness, maintenance mode, policy epoch, and actuator
          identity.</t>
        <t>Finality Sink: the protected controller, safety PLC boundary,
          actuator interface, motor controller, or other component that
          first creates the physical effect.</t>
        <t>Result: calculation of a control command is not treated as
          authority for physical actuation.</t>
      </section>

      <section anchor="wf-robotics" title="Robotics, Vehicles, and Autonomous Machines">
        <t>A planning model or autonomous controller generates a motion or environment-changing action.</t>
        <t>Candidate Act: steering, braking, acceleration, robotic motion,
          payload release, door actuation, drone command, or other kinetic
          operation.</t>
        <t>Protected validation: may check operating mode, safety
          envelope, actor identity, sensor or state freshness, geofence,
          destination, policy epoch, and permitted actuator scope.</t>
        <t>Finality Sink: the motor controller, drive-by-wire interface,
          robotic actuator interface, or equivalent consequence
          boundary.</t>
        <t>Result: a planner may propose the action without holding
          unrestricted final actuation authority.</t>
      </section>

      <section anchor="wf-health" title="Healthcare and Safety-Critical Systems">
        <t>A clinical application, AI model, device controller, or workflow prepares an operation affecting a patient-facing system.</t>
        <t>Candidate Act: a device-setting change, medication-device
          instruction, data disclosure, alert suppression, or
          safety-critical workflow action.</t>
        <t>Protected validation: may verify device identity, clinician or
          workflow authority, patient context, purpose, permitted range,
          freshness, policy state, and safety constraints.</t>
        <t>Finality Sink: the medical-device controller, protected
          workflow dispatcher, disclosure gateway, or equivalent first
          consequence boundary.</t>
        <t>Result: an AI recommendation and an externally effective
          clinical-device action remain distinct stages.</t>
      </section>
    </section>

    <section anchor="threat-model" title="Threat Model and Adversarial Analysis">
      <t>
        This section enumerates the adversary classes and failure classes
        the architecture is intended to resist, states the corresponding
        assumption or guarantee, and gives adversary-facing pseudocode for
        the attack and the corresponding Finality-Sink defense.  It is
        organized around the properties an Execution Handle and a
        Finality Sink are expected to provide: non-bearer scoping,
        freshness, revocability, act-binding, and sink-binding.
      </t>

      <section anchor="threat-assumptions" title="Adversary Model and Assumptions">
        <t>The following adversary capabilities are assumed in scope:</t>
        <ul>
          <li>full control over an ordinary (non-protected) compute
            environment, including an AI agent, application process, or
            cloud workload;</li>
          <li>the ability to observe and replay network traffic on
            unprotected paths;</li>
          <li>the ability to construct arbitrary Candidate Acts, including
            malformed or misleading purpose/destination fields;</li>
          <li>the ability to attempt to reuse, forward, or present a
            captured Execution Handle in a different context, destination,
            or sink; and</li>
          <li>the ability to attempt requests during known windows of
            policy change (for example, immediately after a revocation).</li>
        </ul>
        <t>The following are explicitly out of scope or treated as trust
          anchors, consistent with <xref target="sec-considerations"/>:</t>
        <ul>
          <li>full compromise of the Protected Enforcement Domain itself
            (protected-domain compromise is discussed as a residual risk,
            not defended against by this architecture alone);</li>
          <li>physical extraction of key material from correctly
            functioning protected hardware; and</li>
          <li>weaknesses in the underlying cryptographic primitives
            themselves.</li>
        </ul>
      </section>

      <section anchor="threat-replay" title="T1: Replay of a Previously Authorized Act">
        <t>
          <strong>Attack.</strong> An adversary captures a
          valid Execution Handle and its associated Candidate Act and
          resubmits them later, attempting to trigger the effect a second
          time.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack
captured = intercept(candidate, authority)
sleep(arbitrary_delay)
resubmit(captured.candidate, captured.authority)   # attempt #2

# Defense (Finality Sink, Step 8-10 of Section 11.1)
if authority.nonce_or_counter is already consumed:
    return DENY   # single-use state blocks attempt #2
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> Single-use nonce or
          counter consumption is atomic with effectuation, so a captured
          Execution Handle cannot be reused after its first successful
          consumption at its bound Finality Sink.
        </t>
      </section>

      <section anchor="threat-toctou" title="T2: Time-of-Check to Time-of-Use (TOCTOU) Act Substitution">
        <t>
          <strong>Attack.</strong> An adversary obtains
          validation for a low-risk Candidate Act (for example, exporting
          a small, permitted dataset) and then attempts to substitute a
          different, higher-risk effect (a larger dataset, a different
          destination) at the moment of release, hoping the sink trusts
          the earlier validation result without rechecking the act
          itself.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack
authority = get_valid_authority(low_risk_candidate)
malicious_candidate = mutate(low_risk_candidate,
                              destination="attacker.example",
                              resource_scope="ALL_RECORDS")
finality_sink_receive(malicious_candidate, authority, sink_state)

# Defense (Step 9, and finality_sink_receive() in Section 11.2)
reconstructed_digest = canonical_digest(
    malicious_candidate.load_bearing_attributes)
if reconstructed_digest != authority.candidate_act_digest:
    return DENY   # digest mismatch: the substituted act is rejected
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> The Finality Sink
          recomputes the act digest from sink-visible attributes rather
          than trusting a caller-supplied description of the act,
          closing the gap between what was validated and what is actually
          released.
        </t>
      </section>

      <section anchor="threat-sink-sub" title="T3: Finality-Sink Substitution">
        <t>
          <strong>Attack.</strong> An adversary obtains a
          valid Execution Handle scoped to one Finality Sink (for
          example, a low-security internal export path) and attempts to
          present it at a different, more consequential sink (for example,
          direct external egress) that was never the intended release
          boundary.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack
authority = get_valid_authority(
    candidate, finality_sink_id="internal-export")
finality_sink_receive(
    candidate, authority,
    sink_state=SinkState(sink_id="external-egress"))

# Defense
if authority.finality_sink_id != sink_state.sink_id:
    return DENY
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> Sink-binding makes the
          Execution Handle meaningless outside the specific Finality Sink
          it was issued for, preventing lateral reuse across release
          boundaries of differing consequence.
        </t>
      </section>

      <section anchor="threat-stale-policy" title="T4: Stale Authorization After Policy or Revocation Change">
        <t>
          <strong>Attack.</strong> An actor's authority is
          revoked (for example, an employee is offboarded, an agent is
          suspended, a destination is blacklisted) but the actor attempts
          to use an Execution Handle issued before the revocation.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack
authority = get_authority_issued_before_revocation(candidate)
revoke_actor(candidate.actor_id)             # policy change
finality_sink_receive(candidate, authority, sink_state)

# Defense
if authority.policy_epoch != sink_state.policy_epoch:
    return DENY
if authority.revocation_epoch != sink_state.revocation_epoch:
    return DENY
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> Binding the Execution
          Handle to a policy epoch and a revocation epoch, and requiring
          the Finality Sink to hold current epoch state, ensures a policy
          or revocation change becomes effective at the next
          effectuation attempt rather than only at the next Execution
          Handle issuance.
        </t>
        <t>
          <strong>Residual risk.</strong> If the sink's local
          epoch state is itself stale (for example, due to a partitioned
          network preventing epoch propagation), a revoked actor may
          continue to pass this check until the sink's epoch state
          catches up.  Deployments with a low tolerance for this window
          SHOULD favor short epoch-propagation intervals or synchronous
          epoch lookups for the highest-consequence operation classes.
        </t>
      </section>

      <section anchor="threat-forged-evidence" title="T5: Forged or Fabricated Validation Evidence">
        <t>
          <strong>Attack.</strong> An adversary who controls
          the ordinary compute environment fabricates an Execution Handle
          or validation-evidence record without having gone through the
          Protected Enforcement Domain.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack
forged_authority = ExecutionAuthority(
    candidate_act_digest=digest(candidate),
    permitted_effect="EXPORT_ALL",
    non_bearer=true, ...)   # never issued by a PED

# Defense
if not verify_validation_evidence(authority):
    return DENY   # sig/MAC verification against the PED's key fails
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> The Finality Sink
          verifies validation evidence cryptographically against keys or
          attestation roots controlled by the Protected Enforcement
          Domain, not against anything the ordinary compute environment
          can fabricate.  This is the property that requires the
          Protected Enforcement Domain to be genuinely protected (see
          <xref target="threat-assumptions"/>): if the ordinary compute
          environment can extract or spoof the PED's signing capability,
          this defense fails, which is why PED integrity is treated as a
          trust anchor rather than something this layer alone
          guarantees.
        </t>
      </section>

      <section anchor="threat-downgrade" title="T6: Silent Downgrade / Fail-Open Under Load or Incident">
        <t>
          <strong>Attack.</strong> Rather than attacking the
          cryptography, an adversary induces operational conditions (load
          spikes, timeouts, an incident-response scramble) under which an
          operator or an automated system quietly relaxes a Finality Sink
          from strict mode to permissive or observe mode (see <xref
          target="legacy-downgrade"/>) to "unblock" traffic, without an
          auditable decision to do so.
        </t>
        <sourcecode type="pseudocode"><![CDATA[
# Attack surface: an on-call engineer, under pressure, flips
# sink_state.mode from STRICT to PERMISSIVE to relieve a queue,
# without a tracked change record.

# Mitigation pattern
def set_sink_mode(sink_state, new_mode, actor, justification):
    if new_mode is LESS_STRICT_THAN(sink_state.mode):
        require_explicit_authorization(actor, justification)
        emit_audit_event(sink_state.sink_id, sink_state.mode,
                          new_mode, actor, justification)
    sink_state.mode = new_mode
        ]]></sourcecode>
        <t>
          <strong>Guarantee.</strong> This is a
          process/operational control rather than a cryptographic one:
          the architecture does not prevent an operator from choosing to
          weaken enforcement, but it recommends making any such
          weakening an explicit, attributable, audited action rather than
          a silent default, so that a downgrade is itself detectable and
          reviewable.
        </t>
      </section>

      <section anchor="threat-alt-path" title="T7: Alternate Egress / Unverified Substitute Path">
        <t>
          <strong>Attack.</strong> Rather than attacking the
          protected release path, an adversary locates a different,
          unprotected mechanism that produces the same or an equivalent
          external effect (for example, a debug export endpoint, a
          legacy API version, a secondary network interface) that was
          never fitted with a Finality Sink.
        </t>
        <t>
          <strong>Defense posture.</strong> This attack
          cannot be closed by cryptography at a single sink; it requires
          the deployment to enumerate every path capable of producing the
          protected effect and ensure each one is either fitted with an
          equivalent Finality Sink or is itself decommissioned.  <xref
          target="sec-considerations"/> calls this out explicitly:
          protecting one nominal Finality Sink while leaving an unverified
          substitute path available weakens the intended property, and
          this document treats path enumeration as a deployment-time
          responsibility rather than something the protocol pattern can
          discover automatically.
        </t>
      </section>

      <section anchor="threat-summary" title="Threat Summary Table">
        <table>
          <thead>
            <tr><th>ID</th><th>Threat</th><th>Primary defense</th><th>Residual risk</th></tr>
          </thead>
          <tbody>
            <tr><td>T1</td><td>Replay</td><td>Single-use nonce/counter, atomic consumption</td><td>None if nonce store is itself protected</td></tr>
            <tr><td>T2</td><td>Act substitution (TOCTOU)</td><td>Sink-side digest reconstruction</td><td>None if load-bearing attributes are exhaustively enumerated</td></tr>
            <tr><td>T3</td><td>Sink substitution</td><td>Finality-Sink binding check</td><td>None if sink identity is unforgeable</td></tr>
            <tr><td>T4</td><td>Stale authorization</td><td>Policy/revocation epoch binding</td><td>Propagation-delay window on partitioned sinks</td></tr>
            <tr><td>T5</td><td>Forged evidence</td><td>Cryptographic verification against PED root</td><td>Full PED compromise (trust-anchor assumption)</td></tr>
            <tr><td>T6</td><td>Silent downgrade</td><td>Auditable, attributable mode-change control</td><td>Operational/process discipline, not cryptographic</td></tr>
            <tr><td>T7</td><td>Alternate/unverified path</td><td>Deployment-time path enumeration</td><td>Unenumerated paths remain fully unprotected</td></tr>
          </tbody>
        </table>
      </section>
    </section>

    <section anchor="industry" title="Industry and Infrastructure Relevance">
      <t>
        Execution finality is relevant wherever software can prepare an
        act that produces an external, persistent, financial,
        communicative, jurisdictional, or physical consequence.
      </t>

      <section anchor="ind-ai" title="Artificial Intelligence and Agentic Systems">
        <t>Relevant operations include model-output release, tool
          invocation, retrieval actions, code execution, agent-to-agent
          delegation, data export, memory writes, external API calls,
          autonomous workflows, and machine-generated decisions that
          trigger downstream systems.</t>
        <t>Principal benefit: compromise or overreach of the reasoning
          environment does not automatically grant unrestricted
          effectuation authority.</t>
        <t>Representative Finality Sinks: tool gateway, API dispatcher,
          egress broker, memory writer, model-output emitter,
          operating-system broker, or enterprise control point.</t>
      </section>

      <section anchor="ind-telecom" title="Telecommunications, 5G, 6G, and AI-Native Networks">
        <t>Relevant operations include message or packet release, roaming,
          network-slice changes, subscriber-impacting commands, radio
          emission, gateway egress, AI-RAN actions, machine-to-machine
          commands, and non-terrestrial-network operations.</t>
        <t>Principal benefit: authenticated network intelligence can
          remain distinct from final authority to create a network or RF
          consequence.</t>
        <t>Representative Finality Sinks: telecom gateway, SBC, network
          function, user-plane/control-plane boundary, radio chain,
          satellite gateway, or device communication broker.</t>
      </section>

      <section anchor="ind-cloud" title="Cloud, Edge, and Data-Centre Infrastructure">
        <t>Relevant operations include persistent writes, privileged state
          changes, DMA, accelerator transfers, storage actions,
          SmartNIC/DPU operations, tenant egress, infrastructure APIs, and
          confidential-computing boundary transitions.</t>
        <t>Principal benefit: compromise of an application, VM, container,
          model server, or accelerator workload need not automatically
          become authority for every persistent or external effect exposed
          by the infrastructure.</t>
        <t>Representative Finality Sinks: storage controller, memory
          controller, SmartNIC, DPU, hypervisor boundary, accelerator
          interface, secure service, or egress gateway.</t>
      </section>

      <section anchor="ind-payments" title="Payments, Banking, Fintech, and Digital Assets">
        <t>Relevant operations include payments, account transfers,
          settlement, digital-asset movement, CBDC operations, trading
          instructions, escrow release, ledger commitments, and
          machine-generated financial actions.</t>
        <t>Principal benefit: existing payment-domain authorization can be
          composed with additional act-specific enterprise, purpose,
          agent, jurisdiction, destination, and protected-state
          constraints.</t>
        <t>Representative Finality Sinks: payment-release interface,
          settlement gateway, ledger bridge, account-transfer boundary,
          trading gateway, or protected wallet interface.</t>
      </section>

      <section anchor="ind-privacy" title="Data Governance, Privacy, and Cross-Border Data Use">
        <t>Relevant operations include export, disclosure, model access to
          protected datasets, cross-border transfer, data sharing,
          retrieval, publication, and persistent reconstruction of
          protected information.</t>
        <t>Principal benefit: policy about purpose, recipient,
          destination, jurisdiction, and permitted data scope can remain
          technically coupled to the release boundary rather than existing
          only as upstream policy.</t>
        <t>Representative Finality Sinks: data egress gateway, database
          export interface, object-store release boundary, API
          dispatcher, download service, or disclosure broker.</t>
      </section>

      <section anchor="ind-sat" title="Satellite, Space, and Non-Terrestrial Infrastructure">
        <t>Relevant operations include command uplink, RF transmission,
          payload control, routing, cross-link changes, beam
          configuration, and autonomous spacecraft actions.</t>
        <t>Principal benefit: command preparation can be separated from
          authority to create the mission or RF consequence.</t>
        <t>Representative Finality Sinks: command-uplink gateway, RF
          chain, payload controller, protected spacecraft interface, or
          ground-station release point.</t>
      </section>

      <section anchor="ind-ics" title="Industrial Control, Energy, and Critical Infrastructure">
        <t>Relevant operations include process-control commands, breaker
          operations, valve movements, safety-state changes, plant
          configuration, grid control, water-system control, and emergency
          automation.</t>
        <t>Principal benefit: application or AI compromise does not
          automatically create unrestricted physical-control authority.</t>
        <t>Representative Finality Sinks: safety PLC, industrial gateway,
          actuator controller, breaker interface, motor controller, or
          protected control boundary.</t>
      </section>

      <section anchor="ind-robotics" title="Robotics, Vehicles, Drones, and Autonomous Machines">
        <t>Relevant operations include steering, braking, acceleration,
          robotic motion, drone navigation, payload actions, access
          control, and other kinetic effects.</t>
        <t>Principal benefit: a planner or perception system can compute
          an action while final actuation remains dependent on
          independently verified authority and current protected
          state.</t>
        <t>Representative Finality Sinks: drive-by-wire controller, motor
          controller, robotic actuator, flight-control boundary, or
          protected device broker.</t>
      </section>

      <section anchor="ind-health" title="Healthcare and Safety-Critical Digital Systems">
        <t>Relevant operations include device setting changes,
          patient-data disclosure, safety alerts, clinical workflow
          actions, and machine-generated commands to connected medical
          equipment.</t>
        <t>Principal benefit: recommendation, computation, and externally
          effective clinical action can remain distinct authorization
          stages.</t>
        <t>Representative Finality Sinks: device controller, clinical
          workflow dispatcher, protected data gateway, or safety interlock
          boundary.</t>
      </section>

      <section anchor="ind-sec" title="Cybersecurity and Automated Response">
        <t>Relevant operations include account disabling, credential
          rotation, firewall changes, workload isolation, data deletion,
          quarantine, network blocking, and automated incident-response
          actions.</t>
        <t>Principal benefit: a security agent may detect and propose
          remediation without automatically possessing unrestricted
          authority to create a potentially destructive response.</t>
        <t>Representative Finality Sinks: identity-control plane, firewall
          controller, orchestration gateway, storage-delete boundary,
          endpoint-management service, or cloud control plane.</t>
      </section>

      <section anchor="ind-content" title="Content Publication and Machine-Generated Communications">
        <t>Relevant operations include public posting, outbound messaging,
          automated notification, mass communication, email release,
          content publication, and AI-generated customer or citizen
          communication.</t>
        <t>Principal benefit: generating content remains separate from
          authority to publish, transmit, notify, or otherwise make the
          communication externally effective.</t>
        <t>Representative Finality Sinks: publisher, messaging gateway,
          email relay, notification renderer, telecom gateway, or platform
          communication broker.</t>
      </section>

      <section anchor="ind-common" title="Cross-Industry Common Structure">
        <t>
          Although the underlying technologies differ, the same control
          pattern can be applied:
        </t>
        <artwork><![CDATA[
proposed machine operation
    ->
Candidate Act
    ->
Non-Effective State
    ->
protected act-specific validation
    ->
protected validation evidence
    ->
scoped non-bearer effectuation authority
    ->
Finality-Sink verification
    ->
atomic consumption where required
    ->
externally effective consequence
        ]]></artwork>
        <t>
          The proposal is therefore not that every industry must use the
          same protocol message, cryptographic algorithm, hardware root,
          or policy language.
        </t>
        <t>
          The proposed common layer is the invariant that protected
          authorization of the specific act remains a technical dependency
          of the consequence boundary itself.
        </t>
      </section>
    </section>

    <section anchor="sec-considerations" title="Security and Failure Considerations">
      <t>Implementations should consider the threats enumerated in <xref
        target="threat-model"/>, and in addition:</t>
      <ul>
        <li>replay;</li>
        <li>stale authorization;</li>
        <li>compromised applications;</li>
        <li>compromised AI agents;</li>
        <li>forged validation evidence;</li>
        <li>policy rollback;</li>
        <li>nonce reuse;</li>
        <li>quota races;</li>
        <li>destination substitution;</li>
        <li>sink substitution;</li>
        <li>authority forwarding;</li>
        <li>cross-session reuse;</li>
        <li>fail-open behavior;</li>
        <li>bypass paths;</li>
        <li>alternate egress mechanisms;</li>
        <li>protected-domain compromise; and</li>
        <li>denial-of-service attacks.</li>
      </ul>
      <t>
        The ordinary compute environment should not be assumed trustworthy
        merely because it generated the Candidate Act.
      </t>
      <t>
        High-assurance deployments may fail closed when required protected
        authorization cannot be verified.
      </t>
      <t>
        Deployments should also identify equivalent alternate paths that
        could create the same external effect (see <xref
        target="threat-alt-path"/>).  Protecting one nominal Finality Sink
        while leaving an unverified substitute path would weaken the
        intended property.
      </t>
    </section>

    <section anchor="faq" title="Frequently Asked Questions">
      <t><strong>Is execution finality another authentication protocol?</strong>
        No.  Authentication establishes who or what is interacting.
        Execution finality determines whether a specific proposed act is
        authorized to become externally effective.</t>
      <t><strong>Is this a replacement for TLS or HTTPS?</strong>
        No.  TLS and HTTPS remain necessary for protected communication.
        Execution finality addresses the semantic authorization of the
        consequence carried or requested through that protected
        communication (see <xref target="legacy"/>).</t>
      <t><strong>Is this just OAuth with another token?</strong>
        No.  OAuth provides delegated authorization and can strongly
        restrict API access.  Execution finality focuses on the final
        act-specific release dependency at the consequence boundary,
        potentially adding current state, purpose, destination,
        jurisdiction, freshness, and Finality-Sink binding.</t>
      <t><strong>Does EMV already do this?</strong>
        EMV does something importantly similar inside the payment domain:
        transaction-specific cryptographic information and authorization
        are part of deciding whether a payment proceeds.  The proposed
        contribution is not to recreate EMV.  It is to generalize an
        execution-finality abstraction across heterogeneous machine acts
        and to make the protected consequence boundary explicit.</t>
      <t><strong>Why not simply put all checks in the application?</strong>
        Application-level checks can be effective, but a compromised or
        over-privileged application may also possess the path that
        produces the external effect.  Execution finality separates
        ordinary computation from final consequence authority and places
        independent verification at or immediately before the
        effectuation boundary.</t>
      <t><strong>Is the Finality Sink necessarily hardware?</strong>
        No.  It is a functional boundary.  It may be implemented in
        hardware, protected software, an OS broker, API gateway, telecom
        function, storage controller, payment-release component, secure
        enclave, or other system controlling first usable release of the
        effect.</t>
      <t><strong>Does this require blockchain?</strong>
        No.  A ledger can be used for evidence or state anchoring where
        useful, but it is not a baseline requirement.</t>
      <t><strong>Would this make AI systems too slow?</strong>
        Not necessarily.  Slow policy reasoning can occur on the cold
        path.  The effectuation hot path can be reduced to deterministic
        verification, state checks, replay prevention, and bounded
        release (see <xref target="latency"/>).</t>
      <t><strong>What happens if validation infrastructure fails?</strong>
        The assurance profile determines behavior.  For high-consequence
        acts, fail-closed behavior may maintain the Candidate Act in the
        Non-Effective State until required authority can be verified.</t>
      <t><strong>Does adopting this require replacing TLS, OAuth, or EMV deployments already in production?</strong>
        No.  <xref target="legacy"/> describes an additive shim/gateway
        pattern intended for incremental, operation-by-operation
        adoption alongside unmodified legacy mechanisms.</t>
      <t><strong>What is the Internet missing in one sentence?</strong>
        A general cross-domain execution-finality layer that makes
        protected, act-specific authorization a technical prerequisite of
        externally effective machine consequence.</t>
      <t><strong>What is the core invariant?</strong>
        A machine may compute, prepare, or propose an act, but computation
        alone does not create the authority to make that act externally
        effective.</t>
    </section>

    <section anchor="resources" title="Resources">
      <t>
        The following resources provide additional public context, related
        prior disclosure, and a runnable reference implementation for the
        execution-finality architecture described in this document.  They
        are provided for informational context; this Internet-Draft
        defines the architectural discussion independently of any of
        them.
      </t>
      <ul>
        <li>
          EU AI Alliance Futurium community article, <xref
          target="FUTURIUM-EU"/>: "Protecting Europe: A Technical
          Foundation for Digital Sovereignty, Data Protection, and AI
          Governance," discussing the same execution-finality architecture
          in the context of EU digital-sovereignty and AI-governance
          policy.
        </li>
        <li>
          WIPO PatentScope international publication, <xref
          target="WIPO-WO2026150382"/>: WO&nbsp;2026/150382, "Hardware-Rooted
          Execution-Finality System for Sovereign Artificial Intelligence
          Infrastructure, AI-Native Telecommunications and Satellites,"
          the published international patent application corresponding to
          the architecture described in this document.
        </li>
        <li>
          Privacy Finality Reference, <xref
          target="GITHUB-PRIVACY-FINALITY"/>: a public, runnable reference
          implementation of Candidate-Act-based execution-finality
          enforcement, illustrating the Candidate Act, Protected
          Enforcement Domain, Execution Handle, and Finality Sink
          constructs defined in this document.
        </li>
        <li>
          Privacy Finality Reference, release v0.1.0, <xref
          target="GITHUB-PRIVACY-FINALITY-RELEASE"/>: the versioned
          reference-implementation release corresponding to the
          architecture described in this document.
        </li>
        <li>
          Execution-Finality for AI Agents, GPUs, Confidential Computing,
          and Zero-Trust Automation, <xref
          target="DAS-FOUNDATIONAL-EF-IMPL"/>: the primary reference
          implementation from which the detailed methodology,
          architecture-to-code mapping, threat-model testing, and
          benchmark results in <xref target="appendix-refimpl"/> are
          drawn.
        </li>
      </ul>
    </section>

    <section anchor="related-drafts" title="Related Execution-Finality Internet-Drafts">
      <t>
        This document is part of a series of Internet-Drafts by the same
        author applying the Candidate Act / Non-Effective State /
        Protected Enforcement Domain / scoped non-bearer Execution
        Handle / independent Finality Sink architecture described in
        this document to specific domains, regulatory frameworks, and
        neural/agentic-AI surfaces.  They are listed here for
        cross-reference; none of them is incorporated normatively into
        this document, and each remains an independent Work in Progress.
      </t>

      <section anchor="related-foundational" title="Foundational and Cross-Domain">
        <t>
          <xref target="DAS-CANDIDATE-ACT-FINALITY"/>, "The DAS
          Protocols: Candidate Act Finality," and <xref
          target="DAS-PROTOCOLS-ENTERPRISE-AI"/>, "The DAS Protocols:
          Enterprise AI Governance," develop the same foundational
          vocabulary used throughout this document from complementary
          angles.
        </t>
      </section>

      <section anchor="related-privacy" title="Privacy and Regulatory Enforcement">
        <t>
          <xref target="DAS-PURPOSE-EXECUTION-FINALITY"/>, "Data-Purpose
          Laundering Prevention: Execution-Finality for Preventing
          Cross-Domain Data Reuse"; <xref target="DAS-EU-AI-ACT"/>,
          "Technical Execution Enforcement for the EU AI Act"; and <xref
          target="DAS-GLOBAL-PRIVACY"/>, "Global Privacy Execution
          Enforcement," apply the architecture to purpose-limitation,
          EU AI Act high-risk system, and general-purpose privacy
          enforcement respectively.  <xref target="DAS-PRECISION-EGRESS"/>,
          "Precision-Bounded Egress," and <xref
          target="DAS-DIGITAL-SOVEREIGNTY"/>, "Execution-Finality for
          Digital Sovereignty," apply it to data-precision export
          bounds and to digital-sovereignty enforcement.
        </t>
      </section>

      <section anchor="related-telecom" title="Telecommunications and Non-Terrestrial Networks">
        <t>
          <xref target="DAS-AI-NATIVE-6G"/>, "Execution-Finality for
          AI-Native 5G/6G and O-RAN"; <xref target="DAS-6G-CVID"/>, "6G
          Query-Scoped Communication Handles"; <xref
          target="DAS-MAP-DISCOVERY"/>, "Execution-Finality for MAP
          Discovery and Communication"; and <xref target="DAS-NTN-RF"/>,
          "Execution-Finality for Non-Terrestrial Network RF
          Operations," apply the architecture to 5G/6G/O-RAN, query-scoped
          communication handles, MAP discovery, and satellite/NTN RF
          command paths.
        </t>
      </section>

      <section anchor="related-neural" title="Neural, Agentic, and Model-Governance Applications">
        <t>
          <xref target="DAS-HARDWARE-ENFORCED-EF"/>, "Computation Is Not
          Authority: Hardware-Enforced Execution-Finality for Agentic
          AI, MCP Tool Calls, and Industrial Agents," is the most
          directly related companion, applying this document's
          architecture specifically to MCP tool dispatch, computer use,
          memory writes, GPU/accelerator egress, and industrial-agent
          settlement, with a runnable reference implementation and
          threat model of its own.  <xref target="DAS-RATS-EXTRACT"/>,
          "Execution-Finality for Frontier Model Information Extraction
          Control," and its companion <xref
          target="DAS-RATS-OPENAI-ANTHROPIC"/>, "Execution-Finality for
          Frontier Model Information Extraction Control: OpenAI and
          Anthropic," apply it to controlling release of sensitive model
          information.  <xref target="DAS-RATS-ATTESTATION-BND"/>,
          "RATS Attestation-Bound Execution-Finality," binds the
          architecture to RATS attestation evidence.  <xref
          target="DAS-CHILD-SAFE-RENDERING"/>, "Execution-Finality for
          Preventing Unauthorized Rendering of Age-Restricted Content,"
          and <xref target="DAS-AI-INTEROP"/>, "Execution-Finality for
          Third-Party AI Interoperability Under EU DMA Article 6(7),"
          apply it to child-safe content rendering and to third-party AI
          interoperability under EU DMA Article 6(7).  <xref
          target="DAS-AGENTIC-TOOL-BINDING"/>, "tool_use Is Not
          invoke(): Binding Execution-Finality to Agentic Tool Calls";
          <xref target="DAS-ENTERPRISE-AI-OUTPUT"/>, "Execution-Finality
          for Enterprise AI Output"; <xref
          target="DAS-AGENTIC-EXECUTION-FINALITY"/>, "Execution-Finality
          for Agentic AI Systems"; and <xref
          target="DAS-AGENTIC-AI-TOOL-EXEC"/>, "Agentic AI Tool
          Execution-Finality," each bind the architecture to a further
          agentic tool-use or enterprise AI-output surface.
        </t>
      </section>

      <section anchor="related-ot" title="Settlement and Operational Technology">
        <t>
          <xref target="DAS-PAYMENT-FINALITY"/>, "A Signed Instruction
          Is Not Settlement: Finality for Agentic and API Payments," and
          <xref target="DAS-OT-ACTUATION"/>, "Execution-Finality for
          Operational Technology Actuation," apply the architecture to
          agentic/API payment settlement and to OT/industrial-actuation
          command paths.
        </t>
      </section>
    </section>

    <section anchor="iana" title="IANA Considerations">
      <t>This document has no IANA actions.</t>
    </section>

  </middle>

  <back>
    <references title="Informative References">
      <reference anchor="TLS13" target="https://www.rfc-editor.org/info/rfc9846">
        <front>
          <title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
          <author initials="E." surname="Rescorla" fullname="E. Rescorla"/>
          <date year="2026" month="July"/>
        </front>
      </reference>
      <reference anchor="HTTP" target="https://www.rfc-editor.org/info/rfc9110">
        <front>
          <title>HTTP Semantics</title>
          <author initials="R." surname="Fielding" fullname="R. Fielding"/>
          <author initials="M." surname="Nottingham" fullname="M. Nottingham"/>
          <author initials="J." surname="Reschke" fullname="J. Reschke"/>
          <date year="2022" month="June"/>
        </front>
        <seriesInfo name="RFC" value="9110"/>
      </reference>
      <reference anchor="EMV-CHIP" target="https://www.emvco.com/">
        <front>
          <title>EMV Chip and related EMV Chip security documentation</title>
          <author><organization>EMVCo</organization></author>
          <date/>
        </front>
      </reference>
      <reference anchor="EMV-3DS" target="https://www.emvco.com/">
        <front>
          <title>EMV 3-D Secure and related specifications and explanatory material</title>
          <author><organization>EMVCo</organization></author>
          <date/>
        </front>
      </reference>
      <reference anchor="ZENODO-DAS" target="https://zenodo.org/records/22082995">
        <front>
          <title>The Internet Solved Communication.  It Never Solved Authority</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026" month="August"/>
        </front>
      </reference>
      <reference anchor="FUTURIUM-EU" target="https://futurium.ec.europa.eu/en/apply-ai-alliance/community-content/protecting-europe-technical-foundation-digital-sovereignty-data-protection-and-ai-governance">
        <front>
          <title>Protecting Europe: A Technical Foundation for Digital Sovereignty, Data Protection, and AI Governance</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <author><organization>European Commission, Apply AI Alliance, Futurium</organization></author>
          <date year="2026"/>
        </front>
      </reference>
      <reference anchor="WIPO-WO2026150382" target="https://patentscope2.wipo.int/search/en/WO2026150382">
        <front>
          <title>Hardware-Rooted Execution-Finality System for Sovereign Artificial Intelligence Infrastructure, AI-Native Telecommunications and Satellites</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <author><organization>World Intellectual Property Organization, PATENTSCOPE</organization></author>
          <date year="2026"/>
        </front>
        <seriesInfo name="WO" value="2026/150382"/>
      </reference>
      <reference anchor="GITHUB-PRIVACY-FINALITY" target="https://github.com/sangmdas/privacy-finality-reference">
        <front>
          <title>Privacy Finality Reference: A Public Runnable Reference Implementation of Candidate-Act-Based Execution-Finality Enforcement</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
      </reference>
      <reference anchor="DAS-FOUNDATIONAL-EF-IMPL" target="https://github.com/sangmdas/Execution-Finality-for-AI-Agents-GPUs-Confidential-Computing-and-Zero-Trust-Automation">
        <front>
          <title>Execution-Finality for AI Agents, GPUs, Confidential Computing, and Zero-Trust Automation -- Reference Implementation</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
      </reference>
      <reference anchor="GITHUB-PRIVACY-FINALITY-RELEASE" target="https://github.com/sangmdas/privacy-finality-reference/releases/tag/v0.1.0">
        <front>
          <title>Privacy Finality Reference, Release v0.1.0</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
      </reference>

      <reference anchor="DAS-PURPOSE-EXECUTION-FINALITY" target="https://datatracker.ietf.org/doc/draft-das-purpose-execution-finality/">
        <front>
          <title>Data-Purpose Laundering Prevention: Execution-Finality for Preventing Cross-Domain Data Reuse</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-HARDWARE-ENFORCED-EF" target="https://datatracker.ietf.org/doc/draft-das-hardware-enforced-execution-finality/">
        <front>
          <title>Computation Is Not Authority: Hardware-Enforced Execution-Finality for Agentic AI, MCP Tool Calls, and Industrial Agents</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-CANDIDATE-ACT-FINALITY" target="https://datatracker.ietf.org/doc/draft-das-protocols-candidate-act-finality/">
        <front>
          <title>The DAS Protocols: Candidate Act Finality</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-NTN-RF" target="https://datatracker.ietf.org/doc/draft-das-ntn-rf-execution-finality/">
        <front>
          <title>Execution-Finality for Non-Terrestrial Network RF Operations</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-PAYMENT-FINALITY" target="https://datatracker.ietf.org/doc/draft-das-payment-execution-finality/">
        <front>
          <title>A Signed Instruction Is Not Settlement: Finality for Agentic and API Payments</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-PRECISION-EGRESS" target="https://datatracker.ietf.org/doc/draft-das-precision-bounded-egress/">
        <front>
          <title>Precision-Bounded Egress</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-AI-NATIVE-6G" target="https://datatracker.ietf.org/doc/draft-das-ai-native-6g-execution-finality/">
        <front>
          <title>Execution-Finality for AI-Native 5G/6G and O-RAN</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-6G-CVID" target="https://datatracker.ietf.org/doc/draft-das-6g-query-scoped-communication-handles/">
        <front>
          <title>6G Query-Scoped Communication Handles</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-MAP-DISCOVERY" target="https://datatracker.ietf.org/doc/draft-das-map-discovery-communication-finality/">
        <front>
          <title>Execution-Finality for MAP Discovery and Communication</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-RATS-ATTESTATION-BND" target="https://datatracker.ietf.org/doc/draft-das-rats-attestation-bnd-execution-finality/">
        <front>
          <title>RATS Attestation-Bound Execution-Finality</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-CHILD-SAFE-RENDERING" target="https://datatracker.ietf.org/doc/draft-das-child-safe-rendering-finality/">
        <front>
          <title>Execution-Finality for Preventing Unauthorized Rendering of Age-Restricted Content</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-RATS-OPENAI-ANTHROPIC" target="https://datatracker.ietf.org/doc/draft-das-rats-openai-anthropic-extraction/">
        <front>
          <title>Execution-Finality for Frontier Model Information Extraction Control: OpenAI and Anthropic</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-PROTOCOLS-ENTERPRISE-AI" target="https://datatracker.ietf.org/doc/draft-das-protocols-enterprise-ai/">
        <front>
          <title>The DAS Protocols: Enterprise AI Governance</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-RATS-EXTRACT" target="https://datatracker.ietf.org/doc/draft-das-rats-frontier-model-extraction/">
        <front>
          <title>Execution-Finality for Frontier Model Information Extraction Control</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-ENTERPRISE-AI-OUTPUT" target="https://datatracker.ietf.org/doc/draft-das-enterprise-ai-output-finality/">
        <front>
          <title>Execution-Finality for Enterprise AI Output</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-AI-INTEROP" target="https://datatracker.ietf.org/doc/draft-das-execution-finality-ai-interoperability/">
        <front>
          <title>Execution-Finality for Third-Party AI Interoperability Under EU DMA Article 6(7)</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-AGENTIC-TOOL-BINDING" target="https://datatracker.ietf.org/doc/draft-das-agentic-tool-binding/">
        <front>
          <title>tool_use Is Not invoke(): Binding Execution-Finality to Agentic Tool Calls</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-EU-AI-ACT" target="https://datatracker.ietf.org/doc/draft-das-eu-ai-act-execution-enforcement/">
        <front>
          <title>Technical Execution Enforcement for the EU AI Act</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-GLOBAL-PRIVACY" target="https://datatracker.ietf.org/doc/draft-das-global-privacy-execution-enforcement/">
        <front>
          <title>Global Privacy Execution Enforcement</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-DIGITAL-SOVEREIGNTY" target="https://datatracker.ietf.org/doc/draft-das-digital-sovereignty-finality/">
        <front>
          <title>Execution-Finality for Digital Sovereignty</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-AGENTIC-EXECUTION-FINALITY" target="https://datatracker.ietf.org/doc/draft-das-agentic-execution-finality/">
        <front>
          <title>Execution-Finality for Agentic AI Systems</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-OT-ACTUATION" target="https://datatracker.ietf.org/doc/draft-das-ot-actuation-finality/">
        <front>
          <title>Execution-Finality for Operational Technology Actuation</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
      <reference anchor="DAS-AGENTIC-AI-TOOL-EXEC" target="https://datatracker.ietf.org/doc/draft-agentic-ai-tool-execution-finality/">
        <front>
          <title>Agentic AI Tool Execution-Finality</title>
          <author initials="S." surname="Das" fullname="Sangam Das"/>
          <date year="2026"/>
        </front>
        <refcontent>Work in Progress</refcontent>
      </reference>
    </references>

    <section anchor="appendix-fig" title="Reference Architecture Diagram (FIG. 1A-1C)" numbered="true">
      <t>
        This appendix reproduces, in text-artwork form, the three-sheet
        reference architecture drawing (FIG. 1A, FIG. 1B, FIG. 1C)
        corresponding to the execution-finality pipeline described in
        <xref target="architecture"/> through <xref target="sink"/> and
        worked through step-by-step in <xref target="workflow-sequence"/>.
        Reference numerals 100 through 138 are used consistently with the
        underlying patent disclosure referenced in <xref
        target="resources"/> and are cross-referenced against the
        vocabulary of this document in <xref target="appendix-fig-map"/>.
      </t>

      <section anchor="appendix-fig-1a" title="FIG. 1A -- Candidate Act Generation and Staging">
        <artwork name="" type="ascii-art" align="left"><![CDATA[
+--------------------------------------------------------------+
| 100  COMPUTE / WORKLOAD PLANE                                 |
| AI model, application, network function, payment engine,      |
| content system, agent, digital twin, or device                |
+--------------------------------------------------------------+
                            |
                            v
+--------------------------------------------------------------+
| 102  CANDIDATE ACT GENERATED                                  |
| Proposed output, packet, tensor, command, payment, API call,   |
| transmission, memory release, actuator command, rendering      |
| event, storage write, or other act                             |
|                                                                  |
| Status: NON-EFFECTIVE / PENDING                                 |
+--------------------------------------------------------------+
                            |
                            v
+--------------------------------------------------------------+
| 104  NON-EFFECTIVE STAGING / HOLD STATE PLANE                  |
| Candidate Act may be computed, queued, buffered, ranked,        |
| simulated, encrypted, sealed, or provisionally prepared, but     |
| cannot be released through a Finality Sink or cross an           |
| execution-finality boundary.                                     |
+--------------------------------------------------------------+
                            |
                            v
+--------------------------------------------------------------+
| 106  PROTECTED AUTHORITY PLANE / PROTECTED ENFORCEMENT          |
|      DOMAIN                                                      |
| TEE, HSM, secure element, SmartNIC, DPU, secure enclave,          |
| TPM-backed module, FPGA, baseband security domain, protected      |
| controller, or equivalent structure                                |
+--------------------------------------------------------------+
                            |
                            v
+--------------------------------------------------------------+
| 108  HCAD / MACHINE-VERIFIABLE ACT DESCRIPTOR                   |
| Descriptor binds act class, effect class, source, destination,   |
| purpose, jurisdiction, policy epoch, nonce, freshness,            |
| Finality Sink, boundary, scope, and evidence                       |
+--------------------------------------------------------------+
                            |
                     ( CONNECTOR A )
                            |
                            v
                  [ continued on FIG. 1B ]
        ]]></artwork>
      </section>

      <section anchor="appendix-fig-1b" title="FIG. 1B -- Protected Validation and Scoped Capability Issuance">
        <artwork name="" type="ascii-art" align="left"><![CDATA[
                  ( CONNECTOR A )
             [ continued from FIG. 1A ]
                            |
                            v
+--------------------------------------------------------------+
| 110  PROTECTED PREDICATE VALIDATION                             |
| Validates authority, purpose, jurisdiction, consent,             |
| ALF/RBD where applicable, revocation, freshness, policy           |
| epoch, sink binding, boundary binding, runtime evidence,           |
| quota, budget, and protected state                                  |
+--------------------------------------------------------------+
                 |                              |
          FAILS  |                              |  PASSES
                 v                              v
+---------------------------------+   +---------------------------------+
| 112  VALIDATION FAILS             |   | 114  VALIDATION PASSES            |
| Deny, suppress, quarantine,        |   | Continue to protected state,       |
| zeroize, or hold.  No capability   |   | evidence, and capability           |
| released.                           |   | generation sequence.                |
+---------------------------------+   +---------------------------------+
                 |                              |
                 v                              v
+---------------------------------+   +--------------------------------+
| 116  FAIL-CLOSED / DENIAL          |   | 118  PROTECTED STATE UPDATE /    |
|      ENFORCEMENT HANDLING           |   |      CONSUMPTION                  |
| Candidate Act remains non-effective.|   | Nonce, quota, budget, session,    |
| External effect disabled.  No       |   | revocation, monotonic, or replay  |
| scoped non-bearer capability is     |   | state updated/consumed.           |
| released.  Denial evidence or       |   +--------------------------------+
| denial LAVR is committed as                       |
| protected enforcement evidence of                  v
| non-completion; denial-related       +--------------------------------+
| protected state may be advanced,     | 120  PROTECTED VALIDATION        |
| locked, quarantined, or              |      EVIDENCE / LAVR COMMITMENT   |
| consumed-as-denied to prevent        | Protected validation evidence,    |
| replay, rollback, stale retry,       | receipt, or LAVR is committed      |
| substitution, or cross-sink          | before or atomically with scoped   |
| laundering.                          | non-bearer capability availability.|
+---------------------------------+   +--------------------------------+
                                                     |
                                                     v
                                       +--------------------------------+
                                       | 122  SCOPED NON-BEARER            |
                                       |      CAPABILITY AVAILABILITY /     |
                                       |      RELEASE                        |
                                       | Capability is act-bound,             |
                                       | descriptor-bound, sink-bound,        |
                                       | boundary-bound, nonce-bound,          |
                                       | scope-bound, protected-state-bound,  |
                                       | and evidence-bound.                   |
                                       +--------------------------------+
                                                     |
                                                     v
                                       +--------------------------------+
                                       | 124  FINALITY SINK /               |
                                       |      EFFECTUATION PLANE             |
                                       | Memory controller, DMA engine,      |
                                       | PCIe/CXL/NVLink/UALink boundary,    |
                                       | SmartNIC, DPU, UPF/N6 egress,       |
                                       | radio chain, payment terminal,      |
                                       | ledger bridge, renderer, actuator,  |
                                       | API dispatcher, storage writer, or  |
                                       | model-output emitter                 |
                                       +--------------------------------+
                                                     |
                                              ( CONNECTOR B )
                                                     |
                                                     v
                                           [ continued on FIG. 1C ]
        ]]></artwork>
      </section>

      <section anchor="appendix-fig-1c" title="FIG. 1C -- Sink-Side Verification and Effectuation">
        <artwork name="" type="ascii-art" align="left"><![CDATA[
                  ( CONNECTOR B )
             [ continued from FIG. 1B ]
                            |
                            v
+--------------------------------------------------------------+
| 126  SINK-SIDE DESCRIPTOR BUILD / MEASUREMENT                   |
| Finality Sink builds, reconstructs, measures, or verifies a      |
| sink-side descriptor corresponding to the Candidate Act and       |
| local effectuation boundary                                        |
+--------------------------------------------------------------+
                            |
                            v
+--------------------------------------------------------------+
| 128  FINALITY SINK VERIFICATION                                 |
| Verifies scoped capability against exact Candidate Act,          |
| descriptor digest, sink, boundary, nonce, policy epoch,           |
| evidence reference, protected state transition, and scope          |
+--------------------------------------------------------------+
                 |                              |
          FAILS  |                              |  PASSES
                 v                              v
+---------------------------------+   +---------------------------------+
| 132  SINK VERIFICATION FAILS       |   | 134  SINK VERIFICATION PASSES     |
| Candidate Act suppressed,           |   | External effect enabled only      |
| quarantined, zeroized, denied,      |   | within authorized scope.          |
| or withheld.  External effect       |   | Candidate Act may now be          |
| disabled.                            |   | released through the Finality     |
+---------------------------------+   | Sink and cross the execution-     |
                 |                     | finality boundary.                 |
                 v                     +---------------------------------+
+---------------------------------+                    |
| 136  FAIL-CLOSED AT SINK           |                  v
| No transmission, rendering,         |   +---------------------------------+
| write, settlement, emission,        |   | 130  CAPABILITY CONSUMPTION       |
| actuation, dispatch, or release     |   | Capability will be consumed,      |
| occurs.                              |   | invalidated, burned, marked, or   |
+---------------------------------+   | state-advanced before or          |
                                       | atomically with external           |
                                       | effectuation to prevent replay,    |
                                       | reuse, duplicate effectuation, or  |
                                       | cross-sink use.                     |
                                       +---------------------------------+
                                                     |
                                                     v
                                       +--------------------------------+
                                       | 137  SINK-SIDE FINALITY RECEIPT / |
                                       |      OUTPUT LAVR                    |
                                       | Upon successful sink verification, |
                                       | the Finality Sink or protected     |
                                       | enforcement domain may commit      |
                                       | sink-side finality evidence        |
                                       | representing capability            |
                                       | verification, sink identity,       |
                                       | boundary identity, protected-state |
                                       | reference, permitted scope, and    |
                                       | external effectuation status.       |
                                       +--------------------------------+
                                                     |
                                                     v
                                       +--------------------------------+
                                       | 138  EXTERNALLY EFFECTIVE ACT      |
                                       | Act is transmitted, rendered,      |
                                       | written, actuated, settled,        |
                                       | emitted, committed, or otherwise   |
                                       | effectuated.                         |
                                       |                                      |
                                       | Status: EFFECTIVE                    |
                                       +--------------------------------+
        ]]></artwork>
      </section>

      <section anchor="appendix-fig-map" title="Reference Numeral Cross-Reference">
        <t>
          The following table maps each reference numeral in FIG. 1A-1C to
          the corresponding vocabulary defined in the body of this
          document.
        </t>
        <table>
          <thead>
            <tr><th>Ref.</th><th>Drawing element</th><th>Corresponding document term</th></tr>
          </thead>
          <tbody>
            <tr><td>100</td><td>Compute / Workload Plane</td><td>Ordinary compute environment (<xref target="threat-assumptions"/>)</td></tr>
            <tr><td>102</td><td>Candidate Act Generated</td><td>Candidate Act (<xref target="candidate-act"/>)</td></tr>
            <tr><td>104</td><td>Non-Effective Staging / Hold State Plane</td><td>Non-Effective State (<xref target="candidate-act"/>)</td></tr>
            <tr><td>106</td><td>Protected Authority Plane</td><td>Protected Enforcement Domain (<xref target="validation"/>)</td></tr>
            <tr><td>108</td><td>HCAD / Machine-Verifiable Act Descriptor</td><td>Canonical act digest / load-bearing act attributes (<xref target="workflow-pseudocode"/>)</td></tr>
            <tr><td>110</td><td>Protected Predicate Validation</td><td>Protected validation (<xref target="workflow-sequence"/>, Step 5)</td></tr>
            <tr><td>112/116</td><td>Validation Fails / Fail-Closed Denial</td><td>DENY path, Step 11 (<xref target="workflow-sequence"/>)</td></tr>
            <tr><td>114</td><td>Validation Passes</td><td>VALID result (<xref target="workflow-pseudocode"/>)</td></tr>
            <tr><td>118</td><td>Protected State Update / Consumption</td><td>Nonce/quota/revocation state (<xref target="validation"/>)</td></tr>
            <tr><td>120</td><td>Protected Validation Evidence / LAVR</td><td>Validation evidence, Step 6 (<xref target="workflow-sequence"/>)</td></tr>
            <tr><td>122</td><td>Scoped Non-Bearer Capability</td><td>Execution Handle (<xref target="validation"/>)</td></tr>
            <tr><td>124</td><td>Finality Sink / Effectuation Plane</td><td>Finality Sink (<xref target="sink"/>)</td></tr>
            <tr><td>126</td><td>Sink-Side Descriptor Build</td><td>Act-digest reconstruction, Step 9 (<xref target="workflow-sequence"/>; <xref target="threat-toctou"/>)</td></tr>
            <tr><td>128</td><td>Finality Sink Verification</td><td><tt>finality_sink_receive()</tt> (<xref target="workflow-pseudocode"/>)</td></tr>
            <tr><td>130</td><td>Capability Consumption</td><td>Atomic consumption, Step 10 (<xref target="workflow-sequence"/>; <xref target="threat-replay"/>)</td></tr>
            <tr><td>132/136</td><td>Sink Verification Fails / Fail-Closed at Sink</td><td>DENY at sink (<xref target="workflow-pseudocode"/>)</td></tr>
            <tr><td>134</td><td>Sink Verification Passes</td><td>Effectuation within verified scope (<xref target="sink"/>)</td></tr>
            <tr><td>137</td><td>Sink-Side Finality Receipt / Output LAVR</td><td>Optional audit/accountability evidence, Step 12 (<xref target="workflow-sequence"/>)</td></tr>
            <tr><td>138</td><td>Externally Effective Act</td><td>EFFECTUATED result (<xref target="workflow-pseudocode"/>)</td></tr>
          </tbody>
        </table>
      </section>
    </section>

    <section anchor="appendix-refimpl" title="Reference Implementation -- Foundational Architecture Methodology">
      <t>
        This appendix documents, in detail, a hardened reference
        implementation of the foundational execution-finality
        architecture described in this document and diagrammed in <xref
        target="appendix-fig"/>.  It is provided so the architecture can
        be read as executable, inspectable, reproducible, and
        falsifiable, not only as prose.  It is informational: nothing in
        this appendix is a normative requirement of this document, and
        the reference implementation is not itself a claim of hardware
        non-bypassability or of universal production certification (see
        <xref target="refimpl-limits"/>).
      </t>
      <t>
        The full source code is published in a public GitHub
        repository, <xref target="DAS-FOUNDATIONAL-EF-IMPL"/>.
      </t>

      <section anchor="refimpl-objective" title="Objective and Architectural Invariant">
        <t>
          The implementation tests a single architectural invariant: a
          consequence-bearing operation may be computed, prepared,
          buffered, queued, ranked, simulated, encrypted, sealed, or
          otherwise processed, but it remains non-effective until the
          exact Candidate Act is independently verified by the Finality
          Sink controlling the corresponding external-effect boundary.
          The implementation therefore keeps computation, authorization,
          and effectuation as distinct, separately testable stages
          rather than collapsing them into a single
          <tt>authorize() -&gt; token -&gt; execute()</tt> call (<xref
          target="refimpl-not-token"/>).
        </t>
      </section>

      <section anchor="refimpl-derivation" title="Derivation from FIG. 1A-1C and Architecture-to-Code Mapping">
        <t>
          The implementation follows the three-stage drawing in <xref
          target="appendix-fig"/> directly, rather than starting from a
          conventional token framework and renaming its components.  The
          implemented sequence is:
        </t>
        <artwork name="" type="ascii-art" align="left"><![CDATA[
Compute / Workload Plane
   -> Candidate Act
   -> Non-Effective Hold
   -> Protected Authority / PED
   -> HCAD
   -> Protected Predicate Validation
   -> Protected-State Transition
   -> Validation Evidence / LAVR
   -> Scoped Capability
   -> Finality Sink
   -> Sink-Side Descriptor Reconstruction
   -> Independent Verification
   -> Capability Consumption
   -> Sink Receipt
   -> External Effect
        ]]></artwork>
        <t>
          The Candidate Act is initially non-effective.  The protected
          authority validates predicates and advances protected state.
          Evidence is committed before or atomically with capability
          availability.  The Finality Sink independently reconstructs
          the local descriptor, verifies the exact Candidate Act and all
          load-bearing bindings, consumes the capability, and only then
          permits the external effect.
        </t>
        <t>
          <xref target="appendix-refimpl-map"/> gives the exact mapping
          between the foundational architecture elements used elsewhere
          in this document and the corresponding runnable construct.
        </t>
        <table anchor="appendix-refimpl-map">
          <thead>
            <tr><th>Foundational architecture element</th><th>Runnable implementation</th></tr>
          </thead>
          <tbody>
            <tr><td>Compute / Workload Plane</td><td>Any producer capable of constructing <tt>CandidateAct</tt></td></tr>
            <tr><td>Candidate Act</td><td>Immutable <tt>CandidateAct</tt> dataclass</td></tr>
            <tr><td>Non-Effective State</td><td><tt>ActStatus.NON_EFFECTIVE</tt></td></tr>
            <tr><td>Protected Authority / PED</td><td><tt>ProtectedAuthority</tt></td></tr>
            <tr><td>HCAD / machine-verifiable descriptor</td><td><tt>HCAD</tt> + <tt>build_hcad()</tt></td></tr>
            <tr><td>Protected Predicate Validation</td><td><tt>Policy.validate()</tt></td></tr>
            <tr><td>Protected State</td><td><tt>ProtectedState</tt></td></tr>
            <tr><td>Protected State Transition</td><td><tt>StateTransition</tt></td></tr>
            <tr><td>Validation Evidence / LAVR</td><td><tt>ValidationEvidence</tt></td></tr>
            <tr><td>Evidence commitment</td><td><tt>EvidenceStore</tt></td></tr>
            <tr><td>Scoped capability</td><td><tt>Capability</tt></td></tr>
            <tr><td>Strict non-bearer profile</td><td><tt>PresentationProof</tt></td></tr>
            <tr><td>Finality Sink</td><td><tt>FinalitySink</tt></td></tr>
            <tr><td>Sink-side descriptor reconstruction</td><td>Sink-local <tt>build_hcad()</tt></td></tr>
            <tr><td>Replay consumption</td><td><tt>InMemoryConsumptionStore</tt> / <tt>SQLiteConsumptionStore</tt></td></tr>
            <tr><td>Effect boundary</td><td>Guarded effectors (<xref target="refimpl-effectors"/>)</td></tr>
            <tr><td>Output / finality receipt</td><td><tt>SinkReceipt</tt></td></tr>
            <tr><td>External effect</td><td>Bound effect handle invoked only after sink verification and claim</td></tr>
          </tbody>
        </table>
      </section>

      <section anchor="refimpl-not-token" title="Why the Implementation Is Not Just authorize() -&gt; token -&gt; execute()">
        <t>
          The reference keeps decision, state, evidence, authority,
          presentation, sink verification, replay consumption, and
          effectuation as separately represented stages.  This allows
          tests to mutate each stage independently and determine whether
          the effect boundary still fails closed.  A signature alone is
          never treated as sufficient: the sink verifies semantic
          consistency among the Candidate Act, HCAD, policy epoch,
          evidence, protected-state transition, sink identity, boundary
          identity, nonce, scope, and time bounds (<xref
          target="refimpl-sink-sequence"/>).
        </t>
      </section>

      <section anchor="refimpl-languages" title="Implementation Languages">
        <t>
          Three runtimes are intentionally included so that no single
          language's own bugs can validate themselves:
        </t>
        <table>
          <thead>
            <tr><th>Runtime</th><th>Role</th></tr>
          </thead>
          <tbody>
            <tr><td>Python 3.11+</td><td>Complete, readable reference implementation (state machine)</td></tr>
            <tr><td>Go 1.23.2</td><td>Independent infrastructure-oriented verifier</td></tr>
            <tr><td>Node.js 22.16.0</td><td>Independent application/runtime verifier</td></tr>
          </tbody>
        </table>
        <t>
          Python contains the complete state machine; Go and Node
          independently reproduce the portable canonicalization and
          verify deterministic cryptographic and finality vectors.
          Python was chosen for the complete reference for auditability
          and readability, not because it is asserted to be the optimal
          production implementation for every latency class: for a
          100-microsecond device or accelerator path, a production
          implementation would more plausibly be native code, firmware,
          kernel code, SmartNIC/DPU logic, FPGA logic, or another
          device-resident implementation.  A single-language test suite
          can be self-consistent while still being wrong (Python could
          serialize a structure incorrectly and another Python function
          could reproduce the same mistake), which is why Go
          independently verifies canonicalization, SHA-256, HMAC, and
          complete portable Finality Sink vectors -- Go is also directly
          relevant to networking, gateways, cloud infrastructure,
          sidecars, and telecom control-plane software, and its
          Unicode-normalization dependency is vendored so conformance
          tests can run without Internet access.  Node.js was included
          because JavaScript/TypeScript ecosystems are common in APIs,
          AI-agent tool systems, service gateways, and application and
          cloud control planes; the Node canonicalizer explicitly avoids
          relying on JavaScript's ordinary UTF-16 lexical ordering for
          security-bound object keys.
        </t>
      </section>

      <section anchor="refimpl-candidate-model" title="Candidate Act Data Model and Deterministic Test Parameters">
        <t>
          The Candidate Act represents the concrete proposed consequence,
          not merely a generic permission:
        </t>
        <table>
          <thead><tr><th>Parameter</th><th>Meaning</th></tr></thead>
          <tbody>
            <tr><td><tt>act_id</tt></td><td>Candidate identifier</td></tr>
            <tr><td><tt>act_class</tt></td><td>Operation type</td></tr>
            <tr><td><tt>effect_class</tt></td><td>External consequence class</td></tr>
            <tr><td><tt>source</tt></td><td>Workload/agent/service generating the act</td></tr>
            <tr><td><tt>destination</tt></td><td>Exact consequence destination</td></tr>
            <tr><td><tt>purpose</tt></td><td>Authorized purpose</td></tr>
            <tr><td><tt>jurisdiction</tt></td><td>Applicable jurisdiction</td></tr>
            <tr><td><tt>policy_epoch</tt></td><td>Policy version</td></tr>
            <tr><td><tt>nonce</tt></td><td>Replay-resistant nonce</td></tr>
            <tr><td><tt>issued_at_ns</tt></td><td>Candidate creation time</td></tr>
            <tr><td><tt>freshness_ns</tt></td><td>Candidate validity interval</td></tr>
            <tr><td><tt>sink_id</tt></td><td>Intended Finality Sink</td></tr>
            <tr><td><tt>boundary_id</tt></td><td>Intended effect boundary</td></tr>
            <tr><td><tt>scope</tt></td><td>Exact permitted operation scope</td></tr>
            <tr><td><tt>payload</tt></td><td>Exact proposed action/data</td></tr>
            <tr><td><tt>runtime_evidence_digest</tt></td><td>Runtime/attestation evidence binding</td></tr>
            <tr><td><tt>authority_context</tt></td><td>Additional authority context</td></tr>
            <tr><td><tt>status</tt></td><td>Initially <tt>NON_EFFECTIVE</tt></td></tr>
          </tbody>
        </table>
        <t>
          A stable reference Candidate is used for deterministic
          testing: act class <tt>api-call</tt>, effect class
          <tt>network-egress</tt>, source <tt>agent-A</tt>, destination
          <tt>https://example.invalid/payments</tt>, purpose
          <tt>approved-purpose</tt>, jurisdiction <tt>EU</tt>, policy
          epoch 7, sink <tt>sink-A</tt>, boundary <tt>boundary-A</tt>,
          scope <tt>POST:/payments</tt>, payload amount 1000 minor units
          in EUR to beneficiary <tt>B1</tt>, runtime evidence
          <tt>runtime-ok</tt>, freshness 10,000,000,000 ns (10 s), and
          status <tt>NON_EFFECTIVE</tt>.  The deterministic test clock
          uses <tt>NOW = 1,800,000,000,000,000,000</tt> ns, and a typical
          Candidate is issued 10,000 ns before <tt>NOW</tt>, removing
          wall-clock nondeterminism from security tests.
        </t>
      </section>

      <section anchor="refimpl-hcad" title="HCAD and Canonicalization">
        <t>
          The HCAD binds structured consequence context including act
          class, effect class, source, destination, purpose,
          jurisdiction, policy epoch, nonce, issuance/freshness
          information, Finality Sink, boundary, scope, payload digest,
          and runtime-evidence digest.  The implementation uses both a
          whole-Candidate digest and a structured descriptor digest,
          giving independent detection of Candidate mutation and of
          semantic descriptor mismatch.
        </t>
        <t>
          Security-bound structures use a deliberately narrow canonical
          profile: UTF-8 encoding; Unicode NFC normalization;
          deterministic object-key ordering; compact deterministic JSON
          representation; floats rejected; NaN and infinity rejected;
          non-string map keys rejected; duplicate keys created by
          Unicode normalization rejected; portable integers restricted
          to JavaScript's exact integer range, &#177;(2^53-1); unpaired
          surrogate values rejected; and arbitrary bytes rejected from
          the portable cross-language JSON profile.  The local Python
          canonical form and the narrower Python/Go/Node portable
          profile are explicitly distinguished.  Canonicalization
          prevents cryptographic disagreement caused by whitespace,
          object-key order, Unicode-equivalent forms, float rendering,
          parser differences, duplicate-normalized keys, and alternate
          serialization; the reference demonstrates one constrained
          profile rather than inventing a universal wire standard, and a
          standards-track version would need to define a normative
          canonical encoding or adopt an established canonical
          binary/JSON representation.
        </t>
      </section>

      <section anchor="refimpl-policy" title="Policy, Protected State, and Predicate Validation">
        <t>The reference policy uses the following example configuration (demonstration parameters, not normative limits):</t>
        <table>
          <thead><tr><th>Parameter</th><th>Reference configuration</th></tr></thead>
          <tbody>
            <tr><td>Policy epoch</td><td>7</td></tr>
            <tr><td>Purposes</td><td><tt>approved-purpose</tt>, <tt>diagnostic</tt>, <tt>render</tt></td></tr>
            <tr><td>Jurisdictions</td><td>EU, US, IN</td></tr>
            <tr><td>Sinks</td><td><tt>sink-A</tt>, <tt>sink-B</tt></td></tr>
            <tr><td>Boundaries</td><td><tt>boundary-A</tt>, <tt>boundary-B</tt></td></tr>
            <tr><td>Required runtime evidence</td><td><tt>runtime-ok</tt></td></tr>
            <tr><td>Maximum future-clock skew</td><td>1,000,000,000 ns (1 s)</td></tr>
          </tbody>
        </table>
        <t>
          Reference scopes include <tt>POST:/payments</tt>,
          <tt>WRITE:/records</tt>, <tt>DISPLAY</tt>, <tt>PUBLISH</tt>,
          <tt>SEND</tt>, <tt>SPAWN</tt>, <tt>ACTUATE</tt>,
          <tt>SETTLE</tt>, <tt>DMA:RELEASE</tt>, and
          <tt>QUEUE:PUBLISH</tt>.  The policy rejects, among other
          conditions: Candidate not in <tt>NON_EFFECTIVE</tt> state;
          incorrect policy epoch; unauthorized purpose, jurisdiction,
          sink, or boundary; unsupported effect class; unauthorized or
          empty scope; duplicate scope; revoked source; stale Candidate;
          future-dated Candidate beyond permitted skew; invalid
          freshness; and wrong runtime-evidence digest.  Additional real
          deployments may add consent, legal basis, ALF/RBD identity,
          device posture, transaction risk, model identity, data
          classification, and other predicates.
        </t>
        <t>
          <tt>ProtectedState</tt> models state that should reside in a
          rollback-resistant or protected location in production:
          monotonic version (starts at 0), quota (reference default
          1,000), budget (reference default 1,000), and authorization
          cost (reference default 1).  A successful authorization
          advances state: version N to N+1, quota Q to Q-1, budget B to
          B minus cost.  The state-transition identifier
          cryptographically incorporates the relevant before/after
          values, nonce, source, epoch, and Candidate digest.
        </t>
      </section>

      <section anchor="refimpl-evidence" title="Evidence-Before-Capability Ordering, LAVR, and Capability Construction">
        <t>
          The implementation deliberately performs, in this order:
        </t>
        <artwork name="" type="ascii-art" align="left"><![CDATA[
validate Candidate
    |
    v
advance protected state
    |
    v
construct ValidationEvidence
    |
    v
sign evidence
    |
    v
commit evidence
    |
    v
construct/sign capability
    |
    v
make capability available
        ]]></artwork>
        <t>
          It does not issue authority first and attempt to log evidence
          later: if evidence commitment fails, the operation fails closed
          and no usable capability is returned.  The reference evidence
          (the LAVR) includes: <tt>evidence_id</tt> (cryptographic
          evidence identity), <tt>authority_id</tt> (authority issuing
          the decision), <tt>descriptor_digest</tt> (exact HCAD),
          <tt>candidate_digest</tt> (exact Candidate),
          <tt>transition_id</tt> (protected-state transition),
          <tt>policy_epoch</tt>, <tt>decision</tt> (ALLOW/DENY),
          <tt>reasons</tt> (decision rationale), <tt>committed_at_ns</tt>,
          <tt>key_id</tt> (signing-key identity), and
          <tt>signature</tt>.  The evidence store rejects invalid
          signatures and duplicate evidence identifiers.
        </t>
        <t>
          The scoped capability binds: authority identity; Candidate
          digest; descriptor digest; sink identity; boundary identity;
          nonce; permitted scope; policy epoch; evidence identifier;
          protected-state transition identifier; issue time; expiry; and
          signing-key identity.  The default maximum capability TTL is
          5,000,000,000 ns (5 s).  Actual expiry is the minimum of
          Candidate freshness expiry and authority TTL expiry, so
          capability issuance cannot extend Candidate freshness.
        </t>
        <t>
          The dependency-light baseline uses SHA-256 for digests and
          HMAC-SHA256 for deterministic authentication, chosen because
          Python, Go, and Node can independently reproduce the vectors
          with minimal dependencies -- not as a recommendation to share
          one symmetric key across unrelated trust domains.  The
          repository also includes optional Ed25519 support.  Production
          systems should normally separate at least an authority key
          (capability/evidence signing), a presenter key (proof of
          possession), and a sink key (finality-receipt signing).
        </t>
        <t>
          Red-team analysis identified that act-bound + sink-bound +
          single-use does not automatically make an artifact non-bearer:
          an attacker stealing the exact Candidate and exact unused
          capability could potentially race the legitimate presenter.
          The strict profile therefore binds a presenter identity and
          requires a fresh proof over: capability identifier; Candidate
          digest; sink identifier; boundary identifier; nonce;
          presentation timestamp; and presenter key identifier.  Default
          presentation freshness is 2,000,000,000 ns (2 s); tests
          explicitly reject proofs just outside both positive and
          negative freshness windows.
        </t>
      </section>

      <section anchor="refimpl-sink-sequence" title="Finality Sink Verification and Replay Protection">
        <t>
          The Finality Sink owns its own local context -- sink ID
          (<tt>sink-A</tt> in the reference), boundary ID
          (<tt>boundary-A</tt>), policy epoch (7), supported scopes, and
          effect class, all locally configured.  The caller is not
          allowed to dictate the sink's identity; the sink uses its own
          local configuration when reconstructing the HCAD (<xref
          target="threat-sink-sub"/>).  The sink approximately verifies,
          in sequence:
        </t>
        <artwork name="" type="ascii-art" align="left"><![CDATA[
Candidate remains NON_EFFECTIVE
  -> effect class matches local sink
  -> Candidate sink matches local sink
  -> capability sink matches local sink
  -> Candidate boundary matches local boundary
  -> capability boundary matches local boundary
  -> Candidate epoch matches local epoch
  -> capability epoch matches local epoch
  -> Candidate scope matches capability scope
  -> scope is locally supported
  -> nonce matches
  -> capability time is valid
  -> capability does not outlive Candidate
  -> capability signature is valid
  -> optional presenter proof is valid and fresh
  -> Candidate digest matches reconstructed Candidate
  -> HCAD is rebuilt using local sink/boundary
  -> descriptor digest matches locally rebuilt descriptor
  -> evidence exists
  -> evidence signature is valid
  -> evidence decision is ALLOW
  -> evidence authority matches capability authority
  -> evidence Candidate matches capability Candidate
  -> evidence descriptor matches capability descriptor
  -> evidence state transition matches capability state transition
  -> evidence epoch matches capability epoch
  -> protected-state transition is valid
  -> capability is claimed/consumed
  -> external effect is invoked
        ]]></artwork>
        <t>
          This is intentionally stronger than "signature valid implies
          allow."  The Finality Sink does not trust an upstream
          assertion that the descriptor was already checked; it
          reconstructs the effect context using sink-owned identity,
          boundary, epoch, effect class, and scope configuration, which
          lets it detect cross-sink laundering, wrong-boundary
          presentation, local epoch mismatch, unsupported scope,
          post-authorization Candidate mutation, and semantically
          inconsistent but validly re-signed artifacts -- directly
          exercising the T2 and T3 defenses of <xref
          target="threat-toctou"/> and <xref target="threat-sink-sub"/>.
        </t>
        <t>
          Two replay/consumption backends are included.  The in-memory
          backend uses a lock to protect capability claim state.  The
          SQLite durable backend uses SQLite 3.46.1, WAL journal mode,
          <tt>capability_id</tt> as the primary key, <tt>BEGIN
          IMMEDIATE</tt> for the claim transaction, and a 30-second
          connection timeout; duplicate capability identifiers are
          converted into replay rejection.  Replay is exercised under
          contention: 2, 3, 4, 8, 16, 32, and 64 concurrent contenders
          for the in-memory store, and 2, 4, 8, 16, and 32 for the
          SQLite store, plus 2, 3, 5, 10, and 25 sequential replay
          attempts.  The expected invariant in every case is that
          exactly one contender may create the effect and every other
          contender is rejected (directly exercising <xref
          target="threat-replay"/>).
        </t>
        <t>
          The reference uses <tt>VERIFY -&gt; CLAIM/CONSUME -&gt;
          EXTERNAL EFFECT</tt> rather than <tt>VERIFY -&gt; EXTERNAL
          EFFECT -&gt; CONSUME</tt>.  This chooses at-most-once safety
          and avoids the failure mode where an effect occurs, the
          process crashes before consumption, and a retry produces a
          duplicate effect.  The opposite residual is explicitly
          documented: capability consumption may succeed and the process
          may crash before the external effect occurs, producing
          consumed/no-effect.  Systems requiring stronger exactly-once
          semantics should bind <tt>capability_id</tt> to a target-native
          transaction, idempotency key, ledger transaction identifier,
          transactional outbox, or device-resident atomic
          consume-and-release primitive.
        </t>
      </section>

      <section anchor="refimpl-effectors" title="Guarded Effectors and Wide-Channel Threat Surface">
        <t>Nine consequence-boundary simulations are implemented:</t>
        <table>
          <thead><tr><th>Consequence</th><th>Reference effector</th></tr></thead>
          <tbody>
            <tr><td>Network transmission</td><td><tt>NetworkEffector</tt></td></tr>
            <tr><td>Storage mutation</td><td><tt>StorageEffector</tt></td></tr>
            <tr><td>Rendering</td><td><tt>RendererEffector</tt></td></tr>
            <tr><td>Message queue</td><td><tt>QueueEffector</tt></td></tr>
            <tr><td>Process spawning</td><td><tt>ProcessEffector</tt></td></tr>
            <tr><td>Actuation</td><td><tt>ActuatorEffector</tt></td></tr>
            <tr><td>Payment/ledger</td><td><tt>PaymentEffector</tt></td></tr>
            <tr><td>AI/model output</td><td><tt>ModelOutputEffector</tt></td></tr>
            <tr><td>DMA/memory release</td><td><tt>DMAEffector</tt></td></tr>
          </tbody>
        </table>
        <t>
          The ordinary public effect path rejects direct invocation; the
          sink receives a private bound handle.  This proves the
          reference API seam (<xref target="threat-alt-path"/>), not
          physical non-bypassability against privileged attackers -- see
          <xref target="refimpl-limits"/>.
        </t>
        <t>
          A wider deployment threat model additionally covers twenty
          consequence channels: network-egress, storage-write, renderer,
          message-queue, process-spawn, actuator, payment-ledger,
          model-output, DMA/memory-release, webhook, email-send,
          SMS-send, radio-transmit, ledger-bridge, file-export,
          clipboard, print-spool, socket-egress, shared-memory-release,
          and device-command.  Every declared channel records whether it
          is externally effective, sink-mediated, protected by an
          enforcement boundary, and privileged.  Externally effective,
          non-mediated paths are treated as critical; missing or
          non-privileged enforcement boundaries are separately flagged
          -- the reference-implementation instance of alternate-path
          closure (<xref target="threat-alt-path"/>).
        </t>
        <t>
          Eight reference deployment profiles illustrate how the hot
          path/cold path split of <xref target="latency"/> applies at
          different consequence boundaries:
        </t>
        <table>
          <thead>
            <tr><th>Profile</th><th>Example sink</th><th>Latency target</th><th>Example enforcement</th></tr>
          </thead>
          <tbody>
            <tr><td>Embedded control</td><td>actuator</td><td>100 &#956;s</td><td>MCU / secure element</td></tr>
            <tr><td>Accelerator hot path</td><td>DMA/memory release</td><td>500 &#956;s</td><td>GPU/DPU/SmartNIC</td></tr>
            <tr><td>UPF egress</td><td>network</td><td>1 ms</td><td>UPF/N6 or SmartNIC</td></tr>
            <tr><td>API gateway</td><td>network</td><td>2 ms</td><td>reverse proxy/gateway</td></tr>
            <tr><td>Storage writer</td><td>storage</td><td>5 ms</td><td>transactional writer</td></tr>
            <tr><td>Payment finality</td><td>ledger</td><td>10 ms</td><td>payment/ledger bridge</td></tr>
            <tr><td>Cross-region governance</td><td>network</td><td>20 ms</td><td>regional gateway</td></tr>
            <tr><td>Audit-heavy output</td><td>model output</td><td>50 ms</td><td>controlled emitter</td></tr>
          </tbody>
        </table>
        <t>
          These latency values are engineering stress bands, not vendor
          specifications or normative requirements.  Cold-path examples
          include remote attestation collection, certificate-chain
          validation, policy retrieval, policy compilation, trust-anchor
          verification, and configuration distribution; hot-path
          examples include local descriptor reconstruction,
          digest/signature verification, local epoch/state lookup,
          replay claim, and effect commit.  Very tight latency targets
          generally require precomputation and execution near the actual
          protected effect boundary.
        </t>
      </section>

      <section anchor="refimpl-verification" title="Verification Campaign: Test Counts and Methodology">
        <t>
          The hardened implementation contains 481 collected Python
          tests, all reported passing in the recorded run:
        </t>
        <table>
          <thead><tr><th>Test module/category</th><th>Tests</th></tr></thead>
          <tbody>
            <tr><td>Binding integrity</td><td>66</td></tr>
            <tr><td>Canonicalization</td><td>54</td></tr>
            <tr><td>Consequence channels</td><td>36</td></tr>
            <tr><td>Concurrency/replay</td><td>17</td></tr>
            <tr><td>Core architecture</td><td>11</td></tr>
            <tr><td>Defensive branches</td><td>13</td></tr>
            <tr><td>Ed25519</td><td>2</td></tr>
            <tr><td>Fail-closed/fault injection</td><td>16</td></tr>
            <tr><td>Seeded fuzz mutations</td><td>76</td></tr>
            <tr><td>Interoperability</td><td>37</td></tr>
            <tr><td>Non-bearer/PoP</td><td>13</td></tr>
            <tr><td>Policy matrix</td><td>35</td></tr>
            <tr><td>System profiles</td><td>17</td></tr>
            <tr><td>Key-role separation</td><td>2</td></tr>
            <tr><td>Finality Sink adversarial</td><td>43</td></tr>
            <tr><td>Wide-channel surface</td><td>43</td></tr>
            <tr><td><strong>TOTAL</strong></td><td><strong>481</strong></td></tr>
          </tbody>
        </table>
        <t>
          Binding-mutation tests mutate load-bearing Candidate fields
          after authorization -- act ID, act class, effect class,
          source, destination, purpose, jurisdiction, policy epoch,
          nonce, issue time, freshness, sink, boundary, scope, runtime
          evidence, and authority context -- and payload tests
          independently alter amount, currency, beneficiary,
          missing/extra fields, zero/negative values, large integers,
          nested structures, reordered lists, type changes, case
          changes, and whitespace-sensitive values; the original
          capability must never authorize the changed Candidate (the
          reference-implementation instance of T2, <xref
          target="threat-toctou"/>).
        </t>
        <t>
          Many adversarial tests do not merely corrupt signatures -- they
          alter capability or evidence fields and then re-sign the
          malicious artifact with a valid reference key, testing whether
          the sink validates semantics rather than using the weak rule
          "valid signature equals valid authority."  Re-signed attacks
          target authority, Candidate digest, descriptor digest, sink,
          boundary, nonce, scope, epoch, evidence identifier, state
          transition, and timing values -- directly exercising T5,
          <xref target="threat-forged-evidence"/>.
        </t>
        <t>
          Seventy-six deterministic seeded mutation tests (fixed seeds,
          reproducible failures) cover payment-like payload properties
          and destination/context properties; this is not claimed to be
          coverage-guided fuzzing such as AFL/libFuzzer or a complete
          stateful property-fuzz campaign.  Policy variation tests cover
          combinations and boundary values for jurisdictions (EU, US,
          IN), purposes, quota and budget boundaries, valid and
          over-budget costs, source revocation sets, correct and
          incorrect epochs, valid/zero/stale/future freshness, and
          correct/empty/duplicate/unauthorized scopes -- purpose x
          jurisdiction alone creates a 3x3 cross-product.  Sink-focused
          adversarial tests exercise wrong sink IDs, wrong boundaries,
          wrong epochs, restricted scopes, multiple valid and invalid
          time points, altered destinations and scopes, and sinks
          configured with the wrong authority verification material,
          with adversarial epoch values including 0, 1, 6, 8, 9, and
          2^31-1 (covering ordinary off-by-one conditions and extreme
          values).
        </t>
        <t>
          Cross-language interoperability is checked with 20 positive
          deterministic vectors independently verified by Python, Node,
          and Go, exercising canonical representation, UTF-8 bytes,
          SHA-256, and HMAC-SHA256, plus additional vectors covering
          decomposed Unicode values and keys, BMP-versus-supplementary-plane
          key ordering, JSON control characters, <tt>&lt;</tt>,
          <tt>&gt;</tt>, <tt>&amp;</tt>, U+2028/U+2029, and
          canonical-equivalent forms.  A separate nine-case
          canonicalization conformance suite (five required-success, four
          required-rejection cases, including NFC key collision, float
          rejection, and integers outside the portable safe range) is
          executed independently by Node and Go, with corresponding
          Python tests covering the same profile.  Two complete portable
          Finality Sink vectors (a baseline Candidate and a Candidate
          containing decomposed Unicode inside load-bearing material)
          are independently reconstructed and verified end-to-end
          (Candidate to payload digest to HCAD to Candidate digest to
          protected-state transition to validation evidence to
          capability to sink-local context to Finality Sink
          verification) by Node and Go, so the implementation does not
          rely on Python to generate and verify its own artifacts
          exclusively.
        </t>
        <t>
          The hardened run reports 724 Python source statements, 0
          statements missed, 100% statement coverage, via <tt>pytest
          --cov=src/finality_ref
          --cov-report=term-missing:skip-covered -q</tt>.  This does not
          mean 100% security coverage; it means every measured
          executable Python statement was exercised by the test suite.
        </t>
      </section>

      <section anchor="refimpl-benchmark" title="Benchmark Methodology and Results">
        <t>
          The benchmark uses <tt>time.perf_counter_ns()</tt> and
          performs 1,000 warm-up iterations followed by 3,000 measured
          iterations per path, across three paths: canonicalization plus
          SHA-256; Finality Sink verification only; and complete
          authority plus sink plus guarded effectuation.  The benchmark
          Candidate uses a <tt>network-egress</tt> act from
          <tt>bench-agent</tt> to <tt>example.invalid/effect</tt>,
          purpose <tt>bench</tt>, jurisdiction EU, epoch 1, sink
          <tt>bench-sink</tt>, boundary <tt>bench-boundary</tt>, scope
          <tt>SEND</tt>, runtime evidence <tt>runtime-ok</tt>, 60-second
          Candidate freshness, 30-second capability TTL, and quota/budget
          of 1,000,000 to prevent benchmark exhaustion.
        </t>
        <t>The recorded reference environment:</t>
        <table>
          <thead><tr><th>Environment item</th><th>Recorded value</th></tr></thead>
          <tbody>
            <tr><td>Python</td><td>CPython 3.13.5</td></tr>
            <tr><td>Kernel</td><td>Linux 6.18.35</td></tr>
            <tr><td>Architecture</td><td>x86-64</td></tr>
            <tr><td>libc</td><td>glibc 2.41</td></tr>
            <tr><td>CPU</td><td>AMD EPYC 9V74 80-Core Processor (AuthenticAMD)</td></tr>
            <tr><td>Logical CPUs visible</td><td>5 (process affinity CPUs 0-4)</td></tr>
            <tr><td>Visible memory</td><td>6,236,925,952 bytes</td></tr>
            <tr><td>SQLite / OpenSSL</td><td>3.46.1 / 3.5.5</td></tr>
            <tr><td>Node.js / ICU</td><td>22.16.0 / 77.1</td></tr>
            <tr><td>Go</td><td>1.23.2 linux/amd64</td></tr>
            <tr><td>pytest / pytest-cov / coverage</td><td>9.0.2 / 7.0.0 / 7.13.3</td></tr>
            <tr><td>cryptography / setuptools</td><td>46.0.4 / 82.0.1</td></tr>
          </tbody>
        </table>
        <t>The recorded benchmark results:</t>
        <table>
          <thead>
            <tr><th>Operation</th><th>Mean</th><th>p50</th><th>p95</th><th>p99</th><th>Max</th></tr>
          </thead>
          <tbody>
            <tr><td>Canonical SHA-256</td><td>7.98 &#956;s</td><td>7.12 &#956;s</td><td>8.90 &#956;s</td><td>29.37 &#956;s</td><td>233.75 &#956;s</td></tr>
            <tr><td>Sink verify only</td><td>215.32 &#956;s</td><td>197.30 &#956;s</td><td>287.84 &#956;s</td><td>504.20 &#956;s</td><td>1,314.27 &#956;s</td></tr>
            <tr><td>Authority + sink + effect</td><td>1,113.22 &#956;s</td><td>1,054.97 &#956;s</td><td>1,350.46 &#956;s</td><td>1,847.28 &#956;s</td><td>4,037.53 &#956;s</td></tr>
          </tbody>
        </table>
        <t>
          These are reproducible user-space Python reference
          measurements, not certified production measurements for GPU,
          DPU, telecom, payment, embedded, or other target hardware.  The
          benchmark does not establish controlled CPU frequency, turbo
          state, cache topology, NUMA placement, power governor, core
          isolation, virtualization contention, or dedicated accelerator
          usage.
        </t>
      </section>

      <section anchor="refimpl-limits" title="Threat Model, Limitations, and Deployment-Required Items">
        <t>
          The reference implementation's threat model includes Candidate
          mutation, destination substitution, purpose/jurisdiction
          substitution, scope expansion, sink and boundary substitution,
          cross-sink laundering, epoch rollback, stale/future
          capabilities, evidence mutation/deletion, protected-state
          substitution, sequential and parallel replay, capability
          theft, confused-deputy presentation, canonicalization
          disagreement, Unicode collision, downstream crash, direct
          raw-socket bypass, direct database bypass, renderer/debug
          leakage, DMA/P2P bypass, hidden consequence channels, sink
          compromise, key compromise, denial of service, and covert
          channels -- a superset of the threat model in <xref
          target="threat-model"/>.  The reference package classifies
          each item as TESTED (directly exercised in executable tests),
          MITIGATED (design reduces risk but residual remains),
          DEPLOYMENT_REQUIRED (cannot be solved by the user-space
          reference alone), or RESIDUAL/OUT_OF_SCOPE (explicitly
          unresolved).
        </t>
        <t>Principal limitations, stated directly rather than implied:</t>
        <ul>
          <li>Python is not a hardware security boundary.</li>
          <li>The repository cannot automatically discover every hidden effect path.</li>
          <li>HMAC is reference/interoperability crypto, not a universal production key-distribution recommendation.</li>
          <li>Vendor-specific RATS/TPM/TEE/GPU attestation verification remains pluggable rather than fabricated.</li>
          <li>Exactly-once consequences are not universally guaranteed.</li>
          <li>Timing/cache/RF/power and other covert or physical side channels are outside the model.</li>
          <li>A fully compromised privileged Finality Sink remains a fundamental threat.</li>
          <li>Python memory alone cannot provide hardware rollback resistance.</li>
          <li>The canonical JSON profile is deliberately narrow and should become a normative wire profile in a standards-track implementation.</li>
          <li>Runtime Unicode-data versions differ; the current conformance claim is tied to the defined profile and included repertoire, not every future Unicode code point.</li>
          <li>Latency profiles are targets/stress bands, not guarantees.</li>
          <li>481 tests and 100% statement coverage do not prove absence of unknown vulnerabilities.</li>
          <li>The implementation is an engineering realization and does not by itself establish patent scope or legal claim construction.</li>
          <li>Actual non-bypassability requires that every consequence-bearing path converge on a privileged Finality Sink or equivalent enforcement boundary.</li>
        </ul>
        <t>
          A real deployment should be considered incomplete if a raw
          socket, alternate database credential, unmediated renderer,
          DMA mapping, message-broker credential, direct file writer, or
          other external-effect path can bypass the Finality Sink (the
          general alternate-path-closure requirement of <xref
          target="threat-alt-path"/> and <xref
          target="sec-considerations"/>).
        </t>
      </section>

      <section anchor="refimpl-reproduction" title="Reproduction and Falsifiability">
        <t>Representative complete verification commands are:</t>
        <sourcecode type="bash"><![CDATA[
python3 -m compileall -q src
pytest -q

node node/verify.mjs vectors/interop.json
node node/canonical_conformance.mjs \
    vectors/canonicalization_conformance.json
node node/finality_verify.mjs vectors/finality_case.json
node node/finality_verify.mjs vectors/finality_case_unicode.json

cd go
go test -mod=vendor ./...
go vet -mod=vendor ./...
go run -mod=vendor . ../vectors/interop.json
go run -mod=vendor ./cmd/canonicalconformance \
    ../vectors/canonicalization_conformance.json
go run -mod=vendor ./cmd/finalityverify ../vectors/finality_case.json
go run -mod=vendor ./cmd/finalityverify \
    ../vectors/finality_case_unicode.json

python3 examples/demo.py
python3 examples/strict_non_bearer.py
python3 scripts/benchmark.py
        ]]></sourcecode>
        <t>
          The architecture is intentionally falsifiable.  A claimed
          deployment should fail review if an external effect can bypass
          the sink, if sink identity is caller-controlled, if effect
          occurs before final verification, if replay can produce a
          second consequence, if evidence or protected state can be
          substituted without rejection, if epoch downgrade is accepted,
          if scope can be enlarged, if a claimed strict non-bearer
          capability works through mere possession, or if the claimed
          sink is only a user-space wrapper around an otherwise
          unrestricted effect path.
        </t>
        <t>
          The supportable conclusion from the current hardened package is
          that the foundational execution-finality architecture has been
          converted into an executable state machine in which exact
          Candidate Acts remain non-effective until protected validation,
          protected-state advancement, evidence commitment, scoped
          authority generation, sink-local descriptor reconstruction,
          independent effect-time verification, replay consumption, and
          guarded effectuation occur.  The implementation has been
          exercised through hundreds of deterministic adversarial tests,
          concurrency races, failure injections, canonicalization
          attacks, cross-language verifiers, and system/deployment
          variations.  Actual deployment non-bypassability still depends
          on locating the Finality Sink at the real privileged
          consequence boundary.
        </t>
        <table anchor="refimpl-summary-table">
          <thead><tr><th>Verification summary item</th><th>Value</th></tr></thead>
          <tbody>
            <tr><td>Python tests</td><td>481 passed</td></tr>
            <tr><td>Python source statement coverage</td><td>724/724 statements exercised (100%)</td></tr>
            <tr><td>Cross-language positive vectors</td><td>20</td></tr>
            <tr><td>Canonicalization conformance cases</td><td>9</td></tr>
            <tr><td>Complete Finality Sink vectors</td><td>2</td></tr>
            <tr><td>Independent runtimes</td><td>Python + Node.js + Go</td></tr>
            <tr><td>Concurrent replay testing</td><td>up to 64 contenders</td></tr>
            <tr><td>Wide-channel deployment model</td><td>20 consequence channels</td></tr>
            <tr><td>Executable consequence simulations</td><td>9</td></tr>
            <tr><td>Deployment/latency profiles</td><td>8 profiles, 100 &#956;s to 50 ms</td></tr>
            <tr><td>Benchmark</td><td>1,000 warm-up + 3,000 measured iterations per path</td></tr>
          </tbody>
        </table>
      </section>
    </section>

  </back>

</rfc>
