]>

sankalp.gilda@gmail.com

Applications and Real-Time Workload Identity in Multi System Environments audit agent attestation tamper-evident This document defines a record format for AI agent authorization decisions. The format is one in-toto predicate type, signed inside a DSSE envelope. It carries the seven minimum audit fields that the WIMSE AI Identity Management System framework requires, and two properties that make those fields checkable: a canonicalization contract, and both the authorization decision and the observed effect with a derived three-valued agreement between them. That framework places the record format out of scope and takes no IANA action. This document supplies the format. It defines no policy. About This Document Status information for this document may be found at . Discussion of this document takes place on the Workload Identity in Multi System Environments Working Group mailing list (), which is archived at . Subscribe at .

Introduction This document defines one record format for the audit events that Section 11 of requires, and it defines nothing else. It specifies no policy model, no compliance criteria and no retention rule, and it does not extend or amend . The goals are:

• to make an audit record from one deployment comparable with one from another;
• to make "tamper-evident" a property a verifier can test on the bytes it holds;
• to carry the authorization decision and the observed effect in one signed record, so a disagreement between them is detectable;
• to give the seven minimum fields of Section 11 of one member each.

Policy belongs to a deployment, and a record format belongs to everyone who has to read the record. Two implementations that each satisfy Section 11 in their own format produce audit trails that cannot be compared, correlated across a service boundary, or checked by a party that trusts neither producer. Section 11 asks for all three. Comparable has a narrow meaning here. Two records are comparable when a third party holding both can decide, from the bytes alone, whether they describe the same request, whether their decisions agree, and whether either was enforced. The consequence is concrete: two deployments that each hash a request differently cannot join their records on a request digest, so a delegation that crossed between them is reconstructable in neither log. Section 11 of is normative about the existence of agent audit records and silent about their form. It requires that "deployments MUST produce durable audit logs covering authorization decisions and subsequent remediations", that "Audit records MUST be tamper-evident and retained according to the security policy of the deployment", and that audit events record seven minimum fields. Section 12 then places the policy model and document format out of scope, stating that they are "not recommended as a target for standardization within this specification". Section 13 places compliance criteria out of scope, and Section 16 records no IANA actions. sets out the canonicalization contract and the reason the decision and the observed effect belong in one record.

Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Terminology The following terms are used throughout this document. Two of them, observer and decision point, are defined here; the rest are taken from the documents named beside them.

Agent, Tool, Service, Resource, LLM:

as uses them.

Agent identifier:

a WIMSE identifier as defined in .

Statement, subject, predicate:

as uses them.

Observer:

the party that produces a record under this document. An observer watches from a layer the agent cannot address. A host-side view of a guest filesystem, a hypervisor-level read of guest state, and kernel-level supervision below the observed process are such layers. An in-process library, a wrapper the agent links, and an importer holding another party's log are not.

Decision point:

the party that evaluated the authorization request, whatever its architecture.

Interval:

the period between the before-state and the after-state that one record covers.

Tier:

the degree to which a record's own members corroborate what it claims about how it was observed. A verifier derives the tier under the rule in and never reads it from the record.

Every digest in this document is written as lowercase hexadecimal in the algorithm the record declares in its hashAlgorithm member.

Audit Record Specification A record is an in-toto Statement carried in a DSSE envelope . Its predicateType is Sixteen predicate members are defined in . Each of the sixteen is required unless a rule in that section makes it conditional, no member has a default, and a verifier MUST NOT supply one for an absent member (vector F1). Two members are conditional on a sibling value, resource.argumentsDigest and correlation.externalAnchor, and each is specified where it is defined. A verifier MUST reject a value outside any closed vocabulary this document defines, and MUST NOT ignore the member (vector V1). The closed vocabularies reuse terms registered in .

Canonical form Two implementations derive the same bytes from the same Statement only if they agree on the serialization and on what makes a Statement malformed. Both are fixed below.

JSON profile Producers and verifiers MUST canonicalize the Statement with , and the signature covers those bytes and no other serialization (vector T2). Producers and verifiers MUST enforce the I-JSON safe-integer profile: an integer of magnitude at or above 2^53 makes the Statement malformed (vector T5).

Duplicate members and nesting depth A member name repeated at any depth makes the Statement malformed. A verifier MUST reject such a Statement and MUST NOT retain any one occurrence (vector T3). A Statement nested deeper than 128 levels MUST be rejected (vector T4).

Subject convention A record carries two subject entries. The first is the request, by digest: its name is the correlation identifier and its sha256 digest is the request digest defined in . The second is the after-state root of the interval the predicate carries, and its name is the first entry's name with the suffix /after. A verifier MUST bind on the digest map and MUST NOT bind on either name. A name is a correlation identifier a producer chooses; a digest is a value a verifier recomputes from the bytes it holds. The names exist so that a reader can tell the two entries apart. The second entry MUST be present if and only if the predicate carries an interval (vectors S1 and I1r), and its digest MUST equal the interval's after-state root (vector S2). A decision that permitted nothing, and a decision that was denied, still carry an interval whose before-state and after-state roots are equal and whose write set is empty (vector A2). A consumer therefore reads an absence of effect from the members of a record it holds, and never from a record it does not have.

Timestamps and correlation Every time value in a record MUST be an date-time. A producer SHOULD express it in UTC with the "Z" offset, so that two records from different deployments sort together without a conversion step. The correlation identifier is the first subject entry's name, so one identifier binds the request digest, the interval and the record.

Tamper-evidence A record satisfies the tamper-evidence requirement of Section 11 of when all three of the following hold. The DSSE pre-authentication encoding covers the canonical bytes of the whole Statement, and every one of the seven minimum fields is inside that pre-image. The request digest, the ordered write chain of the effect, and both agreement values are recomputable from other members of the same record. A verifier therefore still refuses a record that the key holder altered and signed again (vector T1). The canonical form is fixed as in , so two verifiers derive identical bytes from identical documents. Any one of the three failing is a refusal. This document does not address the retention half of the Section 11 requirement. Retention is a property of a deployment, and a record cannot assert it about itself. A record under this document SHOULD state that in its doesNotAssert member, so that a reader need not infer coverage.

Mapping to the seven minimum fields The seven minimum fields of Section 11 and the members that carry them

Section 11 field	Members
authenticated agent identifier	agent.id, agent.credentialDigest, agent.authentication, agent.signers
delegated subject, when present	delegation.subject, delegation.subjectKind, delegation.authorityDigest
resource or tool being accessed	resource.kind, resource.id, resource.binding, resource.argumentsDigest
action requested and authorization decision	decision and effect, with the derived agreement
timestamp and correlation identifier	correlation and the interval timestamps
posture assessment or risk state	posture, carrying both vantages and assessedAt
remediation or revocation events and cause	remediation

Each field also carries an evidence partition in fieldEvidence, stating whether the observing substrate covered the value or the producer asserted it. All seven fields can be recorded by an agent about itself. A record that says which ones were is checkable; a record that does not say is not. The fourth field pairs an action with a decision, and this format carries decision, effect and the derived agreement together. A record whose decision and effect disagree is well formed, and the disagreement is visible in signed bytes: A log that carries the decision alone records that case as a clean denial, because it has no other value to disagree with.

Verifying a record A verifier holds a DSSE envelope and reaches a verdict from the bytes inside it. The checks below are the ones this document has already stated, in the order a verifier can apply them without reading a member twice. The envelope's signature comes first, over the canonical bytes of the whole Statement. A statement whose signature does not verify is malformed, and nothing further is read from it. A verifier scored against reports it as malformed (vector T2). The JSON profile comes second: the safe-integer bound of , no member name repeated at any depth, and no nesting past 128 levels. Each of the three makes a Statement malformed, so a verifier that finds one of them has nothing further to check. Membership comes third. Every one of the sixteen members is present unless a rule in makes it conditional on a sibling value, and every value sits inside the closed vocabulary its member declares. The recomputes come last, and a signature cannot supply them. The three that requires come first: a verifier derives the request digest from the four members names and compares it with the first subject entry, it replays the write chain from the before-state root and compares the result with the second subject entry, and it derives both agreement values from the members they are functions of. A fourth recompute binds the prior commitment rather than the record's content. A verifier recomputes the commitment digest, checks that the commitment precedes the interval, and checks that the commitment key is absent from agent.signers. The tier follows from those results. A verifier reads the five clauses of against the members it has just checked and assigns authoritative or voluntary itself. This document requires no particular order and no particular reporting shape. A verifier that stops at the first failure and a verifier that reports every failure are both conformant.

Predicate members

Record identity and hash algorithm recordId is the producer's identifier for this record. It is opaque to a verifier except where the commitment digest is recomputed, which reads it as one of its four inputs. hashAlgorithm names the algorithm every digest in the record is taken under. One value governs the whole record: the subject digests, the credential, authority, policy and posture digests, the interval roots, the write pre-state and post-state digests, and the commitment digest are all taken under it. A record carrying digests in two algorithms is therefore not representable, and that is the point. A verifier comparing two roots has to know they were taken under the same algorithm, and a per-member choice would let a producer choose which comparison a reader could make. issuedAt is the time the producer sealed the record, and it is at or after the interval's sealedAt because the record cannot be issued before the interval it describes has closed. A verifier that does not implement the declared algorithm cannot recompute anything the record binds. It has no verdict to reach on such a record, and reporting that it could not read one is the honest outcome rather than a refusal on the record's content.

Identity, delegation and resource agent.id carries the WIMSE identifier verbatim, and agent.credentialDigest the digest of the credential the identifier was read from. agent.authentication is the mechanism, over the closed set wimse-wpt, http-message-signature, mtls, oauth-access-token, none, drawn from Section 9 of . agent.signers is the set of key identifiers the agent signs its own records with, as the observer knows them, and it MAY be empty. delegation.subjectKind is one of user, system, none. Field 2 of Section 11 is the only conditional one, so an absent delegated subject is conformant and is spelled subjectKind of none beside a subject of the literal none. A subjectKind of none beside any other subject value is malformed and a verifier MUST NOT prefer either member (vector F2). delegation.authorityDigest is required unconditionally, and a decision taken under no authority carries the digest of the explicit deny-all document. resource.kind is one of path, uri, tool, the three shapes the single category of external endpoints in Section 4 of takes. resource.binding of digest-bound MUST carry argumentsDigest, and not-bindable MUST NOT carry it in any spelling, including null and the empty string (vectors F3, F3b and F3c). Where a decision point can canonicalize the arguments of a call, it SHOULD bind them by digest. A tool call whose arguments it cannot canonicalize has nothing to bind, so that call is representable and it cannot reach the strongest tier.

Decision, effect and agreement decision.reported is one of permit, deny, permit-with-conditions. decision.requestDigest MUST equal the first subject entry's sha256 digest and MUST equal the digest over the members action, argumentsDigest, resourceId and resourceKind (vector F4). The hashed object holds argumentsDigest exactly when resource.binding is digest-bound. Under not-bindable it holds the other three members and no argumentsDigest member at all, so every conforming implementation derives one digest for a given request (vector A6). Altering the action, the resource or the arguments after signing therefore breaks a recompute even where the signature was applied again. Each write carries requestDigest: the request digest of the request the observer attributes the write to, or the literal unattributed where the observer cannot attribute it. An attribution is an observation, and an observer that cannot tie a write to a request says so rather than guessing. effect.observed describes this record's request, not the whole interval, and it is one of occurred, none, unknown. It MUST be derivable from the write set: occurred when at least one write is attributed to decision.requestDigest; none when no write is attributed to it and no unattributed write lies inside pathScope; and unknown otherwise. A write attributed to a different request belongs to that request's record and does not enter this one's value (vectors A7 and T1). A value of none beside an empty write set requires the before-state and after-state roots to be equal (vector E1). The ordered write chain MUST reproduce the after-state root from the before-state root (vector E2). A baseResolution of empty-tree MUST carry the empty-tree constant for the declared hash algorithm (vector E3). A member of pathScope MUST NOT contain a glob metacharacter, and a universal scope is the single literal / (vector V2). A write outside pathScope MUST carry inScope of false, which is derived from the path and never a producer opinion (vector V3). agreement is one of agree, disagree, not-exercised, indeterminate, one-sided, and it MUST be derivable from decision.reported and effect.observed by the table below (vectors D1, D2 and D3). posture.agreement MUST be derivable from the two carried postures on the same terms: agree when they are equal byte for byte, disagree when both are present and unequal (vector F6). Deriving agreement from the reported decision and the observed effect

decision.reported	effect.observed	agreement
permit or permit-with-conditions	occurred	agree
deny	none	agree
deny	occurred	disagree
permit or permit-with-conditions	none	not-exercised
any	unknown	indeterminate

A permit allows an action and does not require it, so a permitted call that failed or was never made is not-exercised, and a deny that leaked is disagree. The two are different facts and an incident review needs to tell them apart (vector A9). An unattributed write inside pathScope leaves the observer unable to rule the request's effect in or out, so the record says indeterminate rather than choosing (vector A8). The table never produces one-sided. one-sided is in the closed set and this version never produces it, because decision and effect are both required and neither side can be absent. It is reserved so that a version admitting a record with one side missing does not have to change a closed vocabulary, and a record carrying it under this version is malformed (vector D2). A verifier MUST NOT reject a record because either agreement value is disagree, not-exercised or indeterminate (vectors A3, A8 and A9). A disagreement is the record working, and what it means for admission is a consumer policy decision.

Correlation, posture and remediation correlation.scope is one of producer, cross-party, and it is required because Section 11 asks systems to "correlate events across Agents, Tools, Services, Resources and LLMs", which a producer-scoped identifier cannot do. A record a producer distributes beyond its own deployment SHOULD carry a scope of cross-party. correlation.timeBasis of beacon-anchored MUST carry externalAnchor, and asserted MUST NOT carry it (vector F5). externalAnchor.kind is one of rfc3161, transparency-log, opentimestamps, of which and define the first two. No offline validation rule for an anchor token is defined here, and vector N1 records both readings a conforming verifier can reach. posture.reported and posture.observed are over the closed set no_network, allowlist, sinkhole, unsafe_bypass_egress, each with a digest pinning the posture document. posture.assessedAt carries the time the assessment was made, which gives the reason for. A consumer weighing either posture SHOULD read assessedAt beside it. remediation carries one member per event. Its cause is one of session-revoked, risk-elevated, subject-disabled, token-replay-suspected, policy-changed, operator-action. Its enforcement is one of access-attenuated, session-terminated, tokens-discarded, privileges-reduced, reevaluated, not-enforced. In each member enforcedAt MUST be at or after signalReceivedAt (vector F7). A verifier MUST NOT reject a record because enforcement is not-enforced (vector A4). A record carries that value when a remediation signal arrived and enforcement did not follow it. postEnforcementEffect and postEnforcementRoot make the Section 11 delay requirement checkable by a third party. A revocation that arrived, was recorded, and was followed by an observed effect is a recorded enforcement failure. This document defines no bound on the delay, because Section 11 carries no unit for "undue", and vector N2 records that case as indeterminate.

Observation and tier observation.vantage is one of below-observed, peer, self. An observer that could not read part of pathScope SHOULD name that path in coverage.gaps, because the tier recompute below reads the gap list and not the observer's confidence. observation.priorCommitment is the observer's commitment, made before the interval opened, to the before-state and to a nonce the observer chose. Its committedAt MUST be strictly before the interval's openedAt (vector C2). Its commitmentDigest MUST recompute as the digest over authorityDigest, beforeRoot, recordId and witnessNonce (vector C3). Its keyid MUST NOT appear in agent.signers (vector C1), and that disjointness is the one byte-pure discriminator between an observer and a self-observing party. doesNotAssert is the negative-scope member the sections above refer to: an array of explicit statements about what this record does not claim. A record under this version SHOULD carry two entries. The first entry records that it makes no claim about retention. The second records that it makes no claim that the reported decision is the decision the policy engine evaluated. fieldEvidence carries exactly the seven keys named in the mapping table, each one of substrate-covered or producer-asserted. Both terms are reused unchanged from the field-evidence partition registered in , as the four posture values above are reused from its containment-posture terms. A missing key is malformed (vector FE1), and no key may declare substrate-covered while vantage is self (vector FE2). tier is one of voluntary, authoritative. A verifier MUST recompute it and MUST NOT take the declared value as the tier. Vectors TI1 through TI5 each declare authoritative while failing one clause, so a verifier that reads the declared value passes all five. A record is authoritative if and only if all five of these hold, and voluntary otherwise: vantage is below-observed (vector TI1); priorCommitment is present and complete (vector TI2); pathScope is non-empty (vector TI3); coverage.scopeComplete is true or every gap names a path outside pathScope (vector TI4); and resource.binding is digest-bound (vector TI5). A record declaring authoritative that fails a clause is malformed, and a verifier MUST NOT downgrade it to voluntary (vector TI1). Downgrading would let a producer emit an authoritative-shaped record and rely on the verifier to relabel it. The opposite mismatch is well formed. A record declaring voluntary while meeting all five clauses is not malformed, and a verifier reads it at the tier the recompute gives. Treating the two directions differently is deliberate: a producer that over-claims is relying on somebody else to correct it, and a producer that under-claims is not. A verifier MUST NOT read a voluntary record as evidence that its content corresponds to any independently observed fact (vector A5).

A worked reading of the example The record at the head of reports a write that was denied and happened anyway. Each rule above lands on one of its members. decision.reported is deny, and the single write is attributed to the record's own request, so effect.observed derives as occurred. The third row of the agreement table maps that pair to disagree, which is the value the record carries, so the derivation holds and vector D1 does not apply. posture.reported is sinkhole and posture.observed is allowlist. Both are present and they are unequal, so posture.agreement derives as disagree, which is again the carried value. The tier recompute passes all five clauses. vantage is below-observed; priorCommitment carries all five of its own members; pathScope holds one entry; coverage.scopeComplete is true with no gaps; and resource.binding is digest-bound. The declared authoritative is therefore the tier a verifier derives. The ordering checks hold on the timestamps as written. Vector C2 tests the first: committedAt at 11:03:58Z falls strictly before openedAt at 11:04:01Z. Vector F7 tests the second: enforcedAt at 11:04:09Z falls two seconds after signalReceivedAt at 11:04:07Z. The single write lies under /srv/ledger/, the one member of pathScope, so its inScope of true is derived from the path and vector V3 does not apply. fieldEvidence carries all seven keys, so vector FE1 does not apply, and vantage is not self, so vector FE2 does not either. What the record says, read whole, is that a write was denied and happened anyway, that the posture the decision point read was not the posture an observer saw, and that a revocation signal was enforced two seconds after it arrived. All three are well formed, and a verifier accepts the record.

Security Considerations A record is checkable for internal coherence and says nothing about the world outside its own bytes. Where a consumer needs a fact about that world, it has to establish that fact somewhere else.

The vantage claim is not self-proving The vantage claim in a record is an assertion about the world, and the record makes it coherent with its own members without making it self-proving. A consumer that requires the vantage to be true MUST anchor the observer's key out of band, exactly as it would anchor any signer. Such a consumer MUST read authoritative as coherence with a claimed observation.vantage, and never as proof of one (vector A5).

A producer that observes only itself A producer that observes only itself can satisfy every field of this format, and the observation.priorCommitment member raises the cost of doing so. It binds the before-state, the authority and the record identifier under the observer's signature before the interval opens. A forgery therefore has to be decided on before the forger knows what it will be lying about. It does not reduce the cost to zero, and a producer holding two keys satisfies every clause. That residual is detectable by a key inventory outside the record and by no function of the bytes inside it. A consumer that depends on the vantage SHOULD keep such an inventory.

Withheld rows A record can omit a remediation event, or a claimed access that the observer saw, and no function of a Statement detects a row that was never written. No quantity of extra carried material changes that, because extra material is material a withholding producer also declines to carry. The coverage, fieldEvidence and doesNotAssert members exist so that a blind spot travels where the observer is honest about it. An observer that knows of a blind spot SHOULD record it in the doesNotAssert member. None of these members is a defence against a producer that conceals one.

Well-formed disagreement A disagreement between the reported decision and the observed effect is well formed, as is a disagreement between the two postures, and as is a remediation event recording that enforcement did not occur. A verifier MUST accept all three (vectors A3 and A4). A format that refused to represent a failed enforcement would mean that no record ever reports one. This clause prevents that.

Revocation without a bound Section 11 of requires that revoked or downgraded authorization be enforced "without undue delay" and specifies no bound. This document carries signalReceivedAt and enforcedAt, and defines no bound of its own. A record with an arbitrarily large gap between them is well formed. A consumer SHOULD set a bound on that gap as policy and read a record that exceeds it accordingly.

Relationship to other tamper-evidence mechanisms A signature over canonical bytes detects an editor who cannot sign. A trusted timestamp adds an assertion about when the bytes existed, and an append-only log adds an assertion that they were published. This document requires neither, and a deployment MAY carry a record under this format in such a log. None of the three detects a producer that signed a false record. The recomputes in address that case.

Two implementations that both differ from the canonical form gives the mechanism by which two implementations can share a serialization that is not . Neither party can see the failure from inside it. Every signature each of them produces verifies for the other, and the records fail only for a third party that canonicalizes correctly. A consumer therefore derives the canonical bytes itself and does not accept a producer's report of them. is normative for that reason, and vector T2 is the member that tests it.

Privacy Considerations A record under this document carries an agent identifier, a delegated subject, a resource identifier and a set of paths. The delegated subject in particular may identify a natural person. Deployments SHOULD consider which of these a given consumer needs before distributing a record. The doesNotAssert member is the place to record what a distributed record deliberately omits. The format binds five documents by digest and carries none of them: the credential, the authority document, the policy, and both posture documents. A consumer that needs their content SHOULD resolve them out of band. That separation is deliberate and is the privacy-preserving default, because it lets a record travel to a party entitled to verify the decision without carrying the material the decision was made from. A consumer entitled to the decision receives the digest and resolves the document only if it needs the content.

IANA Considerations This document has no IANA actions. The predicate type is a URI under a namespace the author controls and requires no registration to be used, consistent with the in-toto Attestation Framework's treatment of predicate type identifiers . A registered identifier would be the alternative. It is not proposed here, because a record carries its predicate type inside the bytes its producer signed. A later revision SHOULD NOT move the URI once records carrying it exist, since moving it invalidates every signature over them.

Normative References Defakto Security AWS Zscaler Ping Identity OpenAI Okta This document proposes best practices for authentication and authorization of AI agent interactions. It leverages existing standards such as the Workload Identity in Multi-System Environments (WIMSE) architecture and OAuth 2.0 family of specifications. Rather than defining new protocols, this document describes how existing and widely deployed standards can be applied or extended to establish agent authentication and authorization. By doing so, it aims to provide a framework within which to use existing standards, identify gaps and guide future standardization efforts for agent authentication and authorization. Zscaler Palo Alto Networks This document defines a canonical identifier for workloads, referred to as the Workload Identifier. A Workload Identifier is a URI that uniquely identifies a workload within the context of a specific trust domain. This identifier can be embedded in Workload Identity Credentials, including X.509 certificates and JWT-based tokens, to support authentication, authorization, and policy enforcement across diverse systems. The Workload Identifier format ensures interoperability, facilitates secure identity federation, and enables consistent identity semantics. This document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar. I-JSON (short for "Internet JSON") is a restricted profile of JSON designed to maximize interoperability and increase confidence that software can process it successfully with predictable results. Cryptographic operations like hashing and signing need the data to be expressed in an invariant format so that the operations are reliably repeatable. One way to address this is to create a canonical representation of the data. Canonicalization also permits data to be exchanged in its original form on the "wire" while cryptographic operations performed on the canonicalized counterpart of the data in the producer and consumer endpoints generate consistent results. This document describes the JSON Canonicalization Scheme (JCS). This specification defines how to create a canonical representation of JSON data by building on the strict serialization methods for JSON primitives defined by ECMAScript, constraining JSON data to the Internet JSON (I-JSON) subset, and by using deterministic property sorting. in-toto Secure Systems Lab In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. Informative References This document describes the format of a request sent to a Time Stamping Authority (TSA) and of the response that is returned. It also establishes several security-relevant requirements for TSA operation, with regards to processing requests to generate responses. [STANDARDS-TRACK] This document describes an experimental protocol for publicly logging the existence of Transport Layer Security (TLS) certificates as they are issued or observed, in a manner that allows anyone to audit certificate authority (CA) activity and notice the issuance of suspect certificates as well as to audit the certificate logs themselves. The intent is that eventually clients would refuse to honor certificates that do not appear in a log, effectively forcing CAs to add all issued certificates to the logs. Logs are network services that implement the protocol operations for submissions and queries that are defined in this document. This document describes version 2.0 of the Certificate Transparency (CT) protocol for publicly logging the existence of Transport Layer Security (TLS) server certificates as they are issued or observed, in a manner that allows anyone to audit certification authority (CA) activity and notice the issuance of suspect certificates as well as to audit the certificate logs themselves. The intent is that eventually clients would refuse to honor certificates that do not appear in a log, effectively forcing CAs to add all issued certificates to the logs. This document obsoletes RFC 6962. It also specifies a new TLS extension that is used to send various CT log artifacts. Logs are network services that implement the protocol operations for submissions and queries that are defined in this document. n.d. n.d.

Design rationale Two requirements of this document are not derivable from Section 11 of on its own: the canonicalization contract, and carrying the observed effect beside the reported decision. Neither is restated normatively here.

The canonicalization contract The word "tamper-evident" appears once in and is not defined there. Read narrowly it means a record whose alteration is detectable, which a signature provides. Two gaps remain. A signature over a serialization is only as good as the agreement on which bytes were signed, and that agreement is a property of a written contract between two implementations; neither one's code establishes it. Two implementations can agree with each other on a canonical form and both differ from , and no amount of signing or hash-chaining detects that. Each verifies its own records and rejects the other's, or worse, accepts a record whose meaning it has silently changed. A canonicalization contract is therefore part of the tamper-evidence requirement; it is not an implementation detail, and makes it normative. A signature also says nothing about the producer. The party that holds the signing key can alter a record and sign it again, and every signature check still passes. Detecting that requires fields whose values are recomputable from other fields in the same record, so that an internally inconsistent record is refusable regardless of who signed it. A hash chain catches an alteration by a party with no signing key; only a recompute catches the key holder, and specifies three of them.

The decision and the observed effect The fourth of the seven minimum fields pairs "action requested and authorization decision". A record carrying only the decision is a self-report: it states what an enforcement point concluded, and a deployment that mis-enforces its own conclusion produces a clean audit trail of the decision it failed to apply. Section 11 asks for enough to "reconstruct agent behavior and authorization context after execution", and behaviour is not reconstructable from a decision. This document therefore requires both sides in one record: the decision as reported by the enforcement point, and the effect as observed. It also requires a three-valued agreement between them, which a verifier derives from the two values; it is not a claim the record makes. A decision reported as denied beside an effect observed as having occurred is then a refusable inconsistency in signed bytes. Today it is undetectable. The same construction applies to the sixth field. Section 8 of defines posture assessment as an evaluation performed at credential provisioning, while the sixth field asks for the posture "influencing the decision". A conformant record may therefore carry a posture that was accurate at issuance and inaccurate at decision time, with nothing in the record to say which. Carrying posture as the decision point read it, beside the posture as it was observed and its assessedAt, makes that difference visible without constraining either value.

Why the tier carries five clauses Each clause of the tier recompute closes one route by which a record could claim an observer's vantage while carrying nothing that distinguishes it from a self-report. vantage of below-observed is the claim itself, and the four clauses under it make the claim cost something. The prior commitment binds the before-state before the interval opens, so a producer cannot decide after the fact what it saw. A non-empty pathScope means the record names the ground it covers. A complete coverage claim, or a gap list naming only paths outside that ground, means the record does not quietly exclude the interesting part. And a digest-bound resource means the arguments of the call are pinned. Dropping any one of them admits a record that carries the authority of the rest while resting on nothing. That is why the corpus in carries one reject member per clause.

Conformance vectors The table below is the conformance corpus for this format. Each row gives a member identifier, the accept member it derives from, its input, and the verdict a conforming verifier reaches. A reject differs from the accept member in its from column by one mutation, so refusing every input scores nothing on this corpus. An accept member has no parent and its from column reads root. An indeterminate member has more than one conforming verdict and its row gives each. Every row names the rule it tests. Three rules this document adds have no member in the table: the binding on the digest map in , the requirement in , and the single hash algorithm of . An implementation SHOULD be run against every member of the corpus before it is described as conforming to this document, and the three rules above are checked by reading them. The corpus travels with the predicate schema: the revision of this document that freezes the predicate type URI is the revision that publishes these members in , in that repository's manifest layout. The conformance corpus, one member for every normative rule this document adds

id	from	what it is	expected
A1	root	every member present, permit beside occurred, all five tier clauses met	valid
A2	root	deny beside none, equal roots, empty write set	valid
A3	root	A1 with deny beside occurred and agreement of disagree	valid
A4	root	A1 plus a remediation event with enforcement of not-enforced	valid
A5	root	A1 with vantage of self, no prior commitment, tier of voluntary	valid
A6	root	A1 with binding of not-bindable, argumentsDigest absent from the record and from the request-digest preimage, tier of voluntary	valid
A7	root	A2 plus one in-scope write inside the interval attributed to a different request, roots and chain moved to match	valid, agreement of agree
A8	root	A2 plus one in-scope unattributed write inside the interval, effect.observed of unknown	valid, agreement of indeterminate
A9	root	A1 with permit beside an empty write set, equal roots, effect.observed of none	valid, agreement of not-exercised
F1	A1	A1 with the whole agent member removed	malformed
F2	A1	subjectKind of none beside a named subject	malformed
F3	A1	digest-bound with argumentsDigest removed	malformed
F3b	A6	not-bindable carrying argumentsDigest of null	malformed
F3c	A6	not-bindable carrying argumentsDigest of the empty string	malformed
F4	A1	action changed, requestDigest left at its original value	malformed
F5	A1	beacon-anchored with externalAnchor removed	malformed
F6	A1	two unequal postures declared as agree	malformed
F7	A4	enforcedAt one second before signalReceivedAt	malformed
T1	A1	effect.observed edited to none, writes intact, signed again with the real key	malformed
T2	A1	serialized in declaration order, not order	malformed
T3	A1	a member name repeated at depth three	malformed
T4	A1	nesting 129 levels deep	malformed
T5	A1	an integer of magnitude exactly 2^53	malformed
D1	A1	agreement of disagree with both sides agreeing	malformed
D2	A1	agreement of one-sided with both values present	malformed
D3	A9	agreement of disagree beside permit and none	malformed
S1	A1	second subject entry removed, interval left present	malformed
S2	A1	second subject entry's digest set to the before-state root	malformed
I1r	A1	interval removed, second subject entry left present	malformed
TI1	A1	authoritative declared with vantage of self	malformed
TI2	A1	authoritative declared with no prior commitment	malformed
TI3	A1	authoritative declared with an empty pathScope	malformed
TI4	A1	authoritative declared with a coverage gap inside pathScope	malformed
TI5	A6	authoritative declared on A6	malformed
C1	A1	commitment keyid added to agent.signers	malformed
C2	A1	committedAt one second after openedAt	malformed
C3	A1	witnessNonce changed, commitmentDigest left at its original value	malformed
E1	A2	observed of none with a non-empty write set	malformed
E2	A1	a second write whose pre-state is not the first write's post-state	malformed
E3	A1	empty-tree under sha256 carrying the sha1 constant	malformed
V1	A4	enforcement of quarantined, outside the closed set	malformed
V2	A1	a pathScope member carrying a glob metacharacter	malformed
V3	A1	a write outside pathScope carrying inScope of true	malformed
FE1	A1	six of the seven fieldEvidence keys present	malformed
FE2	A5	substrate-covered declared beside vantage of self	malformed
N1	A1	an anchor token digest carried with no offline validation rule defined	indeterminate
N2	A4	enforcement forty days after the signal, ordering intact	indeterminate

Document History Changes in -01:

• The request-digest preimage under not-bindable is stated: three members, with no argumentsDigest member in any spelling. Under -00 the text named four members and forbade the fourth, so the preimage was open and three spellings gave three digests.
• Each write carries the request digest it is attributed to, or unattributed. effect.observed describes this record's request, and it gains unknown for an unattributed write inside the scope. A write that belongs to another request no longer changes this record's agreement.
• agreement gains not-exercised, for a permit beside no effect, and indeterminate, for an effect the observer could not attribute. Under -00 a permitted call that was never made read as disagree, the value a leaked deny also takes.
• A statement whose signature fails is malformed, so and vector T2 report the same verdict.
• Six members are added to : A7, A8, A9, F3b, F3c and D3.

-00 was the first revision.

Acknowledgments No acknowledgments are recorded for this revision.