]> VERAX TEKNOLOJI LIMITED SIRKETI

Turkey e.dogru@cedulon.com

sec Cedulon agent receipt policy SCITT This document defines the Cedulon Protocol, an audit layer for agent-to-agent commerce. Payment rails such as HTTP 402 flows (x402) and mandate protocols (AP2) already move value. They do not, by themselves, produce a fail-closed policy check and a signed spend receipt that a verifier can reconcile against a rail extract. Cedulon specifies a Trade Manifest (signed offer before payment), a Policy Decision Point with default deny, a Spend Receipt (COSE/CWT claim set after a gated payment), epoch checkpoints, and rail-extract reconciliation that proves completeness against an authenticated rail extract. It also defines a Dispute Evidence Bundle (evidence, not an award) and optional SCITT anchoring. Cedulon is not a competitor to x402 or AP2; it sits above them.

Introduction Note to Readers: This document is submitted as Informational. The author's eventual intended track, if the work is taken up, is a Standards Track profile of COSE and CWT for agent-spend receipts. This -00 does not claim IETF consensus. Agents can now pay. Open HTTP 402 protocols attach stablecoin settlement to ordinary requests. Card networks and processors issue agent-scoped tokens. Google's Agent Payments Protocol (AP2) binds user intent to signed mandates. What is missing is an interoperable audit layer: a machine-checkable answer to "was this spend allowed by policy, against which offer, and what bytes were delivered?" Without that layer, a prompt-injected or looping agent can drain a rail that has already accepted a valid signature. A counterparty can ship the wrong artifact. A transparency log, if used at all, is proprietary. Cedulon fills that gap. It does not clear funds, hold custody, or operate a payment facilitator. An optional escrow actor is defined only as a third-party role interface (). Implementations of this specification MUST NOT take custody of funds or operate escrow (MUST-T8-custody). The completeness claim sits in a long bookkeeping line. Single-entry records (clay tablets, journals) listed events in one place and could not check themselves. Double-entry bookkeeping, set out by Pacioli in 1494 , posts each event to two books so that the books can check each other. Cedulon is a later step: proven completeness, where an external witness (the authenticated rail extract) is machine-checkable against signed spend receipts. Grigg's triple-entry idea (signed receipts as the third entry) is . Cedulon's addition is the completeness and reconciliation proof plus an open standard profile, not a claim to be first. Neighbor drafts are complementary, not substitutes. draft-bates-atp covers tamper-evident causal lineage as a signed DAG. Cedulon is the completeness layer: a spend that never produced a receipt is visible when an authenticated rail extract is reconciled (MUST-T10-1).

Terminology 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. The following terms are used:

Trade Manifest:

A signed statement produced before payment. It binds a description of goods or service, price, currency, acceptance-criteria hash, cancel condition, expiry, and an optional AP2 mandate reference.

Policy Decision Point (PDP):

The function that evaluates a structured spend request against stored policy. The default is deny.

Spend Receipt:

A signed statement produced after a gated payment attempt. It binds payer, payee, amount, currency, policy hash, manifestHash or an explicit noManifest flag, rail payment reference, timestampMs, nonce, prevReceiptHash, and outcome.

Receipt Issuer:

The party that signs Spend Receipts.

Anchor:

An optional SCITT Transparency Service that registers a signed statement and returns a COSE receipt .

Dispute Evidence Bundle:

A package of the Trade Manifest, the Spend Receipt, and a delivery hash. It is evidence for a later human or legal process. It is not an arbitral award and not an escrow release.

Decision Token:

A portable, single-use PDP allow encoded as COSE_Sign1. The claim set binds requestHash, policyHash, expiryMs, nonce, and singleUseId. See .

Rail Extract:

An authenticated list of settlement records for one account, one rail, and one time window. See .

Architecture Cedulon has three control-plane objects and one optional log: PDP --allow/deny--> x402/AP2 rail | v Receipt Issuer --> Spend Receipt | v Anchor / SCITT (optional) ]]> The payer agent never talks to the rail except through an adapter that calls the PDP first (MUST-T5-1).

Policy Decision Point The PDP evaluates structured fields only (MUST-T1-1): amount, currency, payee, tool identifier, nonce, optional manifest hash, and evaluation time. It applies limit, velocity, and scope checks (MUST-T2-1, MUST-T2-2). If the PDP is unreachable, uninitialized, or throws, the result is deny (MUST-T2-3). Denied attempts do not increment success counters (MUST-T2-4). An allow produces a Decision Token whose requestHash covers six fields: amount, currency, payee, tool, nonce, and manifestHash (MUST-T3-4, MUST-T6-1). The token is a COSE_Sign1 object (MUST-T6-4), is single-use (MUST-T6-2), and MAY be carried to the adapter that performs settlement.

Receipt Issuer After the adapter attempts settlement (success or a recorded deny that still needs an audit trail for an allowed-then-aborted path), the Receipt Issuer signs a Spend Receipt over a canonical encoding (MUST-T4-1). Verifiers reject bad signatures and byte mismatch (MUST-T4-2).

Anchor / SCITT Parties MAY register the signed receipt (or a privacy-preserving hash encoding) as a SCITT Signed Statement and attach the COSE receipt (MAY-T4-6). This document does not operate a Transparency Service.

Trade Manifest A Trade Manifest is the commerce analogue of a promise: it is issued before value moves. It is conceptually symmetric to a later Spend Receipt (promise then proof), and it MAY carry an AP2 mandate hash so that user intent and the Cedulon offer stay linked (SHOULD-T8-5). A Trade Manifest MUST bind all of the following (MUST-T8-1):

• goods or service description
• price (integer minor units, encoded as a decimal string matching 0|[1-9][0-9]*)
• currency (ISO 4217 alphabetic or a documented token identifier)
• acceptance-criteria hash (SHA-256 of the exact delivery bytes or of a declared schema instance)
• cancel condition (opaque string agreed by the parties)
• expiry (POSIX milliseconds, expiresAtMs)

It MAY include ap2MandateHash. The corresponding CBOR label is always present; a missing mandate is encoded as CBOR null. The manifest is COSE_Sign1 over a deterministic CBOR claim map (). manifestHash is the SHA-256 of the signed COSE bytes (MUST-T8-7). A spend bound to a manifest MUST be denied if the requested amount or currency differs from the manifest (MUST-T8-2) or if the manifest is expired (MUST-T3-3). A spend that is not bound to a verified manifest MUST be marked noManifest on the receipt and MUST still pass limit, velocity, and scope checks (MUST-T1-2). An implementation MAY refuse all noManifest spend (MAY-T1-4).

Spend Receipt The Spend Receipt claim set is carried in COSE_Sign1 wrapping a CWT-compatible map . New receipts MUST use the COSE profile (). Claims (MUST-T4-3, MUST-T4-4, MUST-T4-7):

Claim	Description
payer	Payer agent identifier
payee	Payee identifier
amount	Minor units as a decimal string 0|[1-9][0-9]*
currency	Currency identifier
policyHash	SHA-256 of the canonical policy document (lowercase hex)
manifestHash	SHA-256 of the signed manifest COSE bytes, or null when noManifest is true
noManifest	Boolean; MUST be true if and only if manifestHash is null
x402PaymentRef	Rail payment reference, or null
timestampMs	POSIX milliseconds
nonce	Unique spend nonce; at least 128 bits of randomness; unique in the issuer scope
prevReceiptHash	Previous receipt hash, or null for the first receipt (SHOULD-T4-5)
outcome	settled or aborted

A receipt with outcome = settled MUST have a non-null x402PaymentRef (MUST-T4-7). An aborted receipt MUST NOT be added into checkpoint totals. All twelve labels in are always present. An empty optional value is encoded as CBOR null, never by omitting the label. receiptHash is the SHA-256 of the receipt's signed COSE bytes, encoded as lowercase hex. Verifiers MUST reject a receipt if the signature fails or if the decoded claim map does not match the presented claims (MUST-T4-2).

Optional payee countersignature A payee MAY attach a countersignature over the issuer's signed Spend Receipt (MAY-T8-9). The profile uses a detached COSE_Sign1 whose payload is a CBOR map with a single private-use label:

Label	Claim	CBOR type
-70401	receiptCose	bstr (exact issuer COSE_Sign1 bytes)

The countersignature uses the header profile in and content type application/cedulon-countersign+cbor. This is a second Sign1 object, not RFC 9052 Countersignature0 (unprotected-header label 11). Countersignature0 would write into the issuer object and change receiptHash after issue, breaking the receipt chain. A detached Sign1 keeps the issuer bytes stable, reuses kid and content-type, and is absent by simply omitting the sibling object. Absence of a countersignature MUST NOT invalidate the issuer receipt (MAY-T8-9). If a countersignature is present, a verifier MUST reject it when the signature fails, when kid or content type does not match the configured payee key, or when label -70401 is not the issuer COSE bytes (MUST-T8-8). A Dispute Evidence Bundle that includes a verified countersignature has stronger evidence that the payee accepted those bytes; the bundle is still not an award (MUST-T8-4).

COSE Profile This profile uses deterministic CBOR Section 4.2.1 (definite lengths, shortest integer form, map keys sorted in bytewise lexicographic order of their encoded keys). Implementations MUST encode only the types used by Cedulon claim maps: null, bool, unsigned and negative integers, UTF-8 text, byte strings, arrays, and maps (MUST-T4-1).

Claim labels Registered CWT claims are not required in -00. Cedulon uses CWT private-use integer labels less than -65536 so that the profile does not occupy the 100-110 registry range. Receipt labels (MUST-T4-3, MUST-T4-4, MUST-T4-7):

Label	Claim	CBOR type
-70001	payer	tstr
-70002	payee	tstr
-70003	amount	tstr
-70004	currency	tstr
-70005	policyHash	tstr (lowercase hex SHA-256)
-70006	manifestHash	tstr / null
-70007	noManifest	bool
-70008	x402PaymentRef	tstr / null
-70009	timestampMs	uint
-70010	nonce	tstr
-70011	prevReceiptHash	tstr / null
-70012	outcome	tstr (settled / aborted)

Checkpoint labels (MUST-T11-1):

Label	Claim	CBOR type
-70101	epoch	uint
-70102	startMs	uint
-70103	endMs	uint
-70104	receiptCount	uint
-70105	chainHeadHash	tstr / null
-70106	totals	map tstr -> tstr
-70107	prevCheckpointHash	tstr / null

Manifest labels (MUST-T8-1):

Label	Claim	CBOR type
-70201	description	tstr
-70202	amount	tstr
-70203	currency	tstr
-70204	acceptanceCriteriaHash	tstr
-70205	cancelCondition	tstr
-70206	expiresAtMs	uint
-70207	ap2MandateHash	tstr / null

Decision Token labels (MUST-T6-4):

Label	Claim	CBOR type
-70301	requestHash	tstr
-70302	policyHash	tstr (lowercase hex SHA-256)
-70303	expiryMs	uint
-70304	nonce	tstr
-70305	singleUseId	tstr

COSE_Sign1 headers The protected header MUST be a deterministic CBOR map containing (MUST-T4-1, MUST-T4-8):

• 1 (alg) = -19 (Ed25519, ; the generic EdDSA value -8 from is deprecated for this profile)
• 3 (content type) = a tstr that distinguishes the payload: application/cedulon-receipt+cbor, application/cedulon-checkpoint+cbor, application/cedulon-manifest+cbor, application/cedulon-decision+cbor, or application/cedulon-countersign+cbor
• 4 (kid) = bstr, mandatory. The profile computes kid as the first eight bytes of SHA-256 over the issuer's SubjectPublicKeyInfo DER. A verifier MUST obtain the public key from an authenticated channel (preconfigured issuer set, directory, or transparency statement) and MUST reject a message whose kid does not match that key.

The unprotected header MUST be empty. The payload MUST be the CBOR encoding of the claim map. The signature is Ed25519 over the COSE Sig_structure ["Signature1", protected, h'', payload].

Decision Token A Decision Token is the portable encoding of a PDP allow. It is COSE_Sign1 with the header profile in and the labels in . All five labels are always present (MUST-T6-4). requestHash MUST be the six-field hash defined for the PDP (MUST-T6-1). policyHash MUST be the SHA-256 of the canonical policy document the PDP evaluated. expiryMs is a Unix time in milliseconds after which the token MUST be treated as expired (SHOULD-T6-3). nonce is the request nonce. singleUseId is the identifier consumed on the first settlement attempt (MUST-T6-2). A party that accepts a Decision Token MUST reject it if the signature fails, if kid does not match a configured PDP key, if the content type is not application/cedulon-decision+cbor, if the decoded claim map does not match the presented claims, or if expiryMs is in the past (MUST-T6-5).

Rail Extract Profile A verifier checks completeness against a rail extract, not against the issuer's own receipts alone (MUST-T10-7).

Record schema Each settlement record MUST contain:

Field	Type
ref	tstr (rail payment reference)
amount	tstr matching 0|[1-9][0-9]*
currency	tstr
timestampMs	uint

Scope An extract is scoped to one account identifier, one rail identifier, and one half-open time window [windowStartMs, windowEndMs).

Authentication The mock rail in the companion implementation signs the extract with Ed25519 over a canonical encoding of the scoped body. A production verifier MUST obtain the extract from the rail or from a signature the rail published (MUST-T10-7). If the extract is missing a verifiable signature, the verifier MUST emit finding unauthenticated-extract. Completeness findings may still be computed, but the completeness guarantee is conditional on the extract being authentic. See .

Reconciliation and Epoch Checkpoints Completeness is the property that, given an authenticated rail extract, every settlement in the extract has a matching settled Spend Receipt, every settled receipt has a matching settlement, receipt and checkpoint hash chains verify, and checkpoint totals equal the sum of settled receipts in the checkpoint window. If a spend occurred without a receipt, the missing receipt is itself the evidence (MUST-T10-2).

Checkpoint claims An epoch checkpoint MUST be COSE_Sign1-signed with the header profile in and MUST bind all of the following (MUST-T11-1): epoch, startMs, endMs, receiptCount, chainHeadHash, totals, and prevCheckpointHash. The checkpoint window is half-open [startMs, endMs) (MUST-T11-7). receiptCount MUST equal the number of receipts (settled and aborted) whose timestampMs falls in that window. chainHeadHash MUST equal receiptHash of the last receipt in that window, or null if the window is empty (MUST-T11-2). totals MUST sum only receipts with outcome = settled.

Genesis and continuity The first checkpoint in a presented chain is the genesis checkpoint of that chain. Its prevCheckpointHash MUST be null. Epoch numbers MUST be consecutive integers. Adjacent windows MUST satisfy next.startMs = prev.endMs (MUST-T11-8). A later checkpoint that omits a prefix of earlier epochs (prefix deletion) is detectable only if an external witness (transparency log) has recorded the missing prefix (MUST-T11-9). Without that witness, T11 guarantees about suppression are conditional.

Verification algorithm A verifier MUST perform these steps in order (MUST-T10-1, MUST-T11-2):

1. If the rail extract signature does not verify, emit unauthenticated-extract and treat the guarantee as conditional (MUST-T10-7).
2. Decode each Spend Receipt COSE_Sign1. Reject if Ed25519 verify fails, if kid does not match the configured issuer key, if the content type is not the receipt type, or if the decoded claim map does not match the presented claims (MUST-T4-2, MUST-T4-8).
3. Walk receipts in issuer order. The first prevReceiptHash MUST be null. Each later prevReceiptHash MUST equal receiptHash of the previous receipt. A miss is receipt-chain-break.
4. Index settled receipts and extract records by ref. A ref that appears more than once on either side is duplicate-ref (MUST-T10-6).
5. For each unique ref, require a one-to-one match on ref AND amount AND currency (MUST-T10-1). Amount or currency mismatch is settlement-mismatch. A settlement with no receipt is settlement-without-receipt (MUST-T10-2). A settled receipt with no extract row is receipt-without-settlement (MUST-T10-3). A settled receipt with a null rail ref is settled-without-ref.
6. Aborted receipts are not matched to extract rows and are not added to totals.
7. Decode each checkpoint. Reject a failed signature. Require receiptCount, chainHeadHash, and totals to match the receipts in [startMs, endMs) as defined above (MUST-T11-2).
8. Every chained receipt MUST fall in exactly one checkpoint window. A gap or double count is window-coverage (MUST-T11-7, MUST-T11-8).
9. Walk checkpoints in epoch order. prevCheckpointHash MUST equal the SHA-256 of the previous checkpoint COSE bytes, or null for genesis (MUST-T11-4).
10. If two successfully verified checkpoints share an epoch number and have different hashes, emit equivocation (MUST-T11-3).
11. If any fail-severity finding exists, the audit MUST fail (MUST-T10-4).

Finding codes

Code	Severity	Meaning
settlement-without-receipt	fail	Extract row has no matching settled receipt
receipt-without-settlement	fail	Settled receipt ref is not on the extract
settlement-mismatch	fail	Same ref, different amount or currency
duplicate-ref	fail	Ref appears more than once on one side
settled-without-ref	fail	outcome is settled and x402PaymentRef is null
receipt-chain-break	fail	Signature or prevReceiptHash failed
checkpoint-total-mismatch	fail	Totals, count, signature, or checkpoint chain failed
checkpoint-head-mismatch	fail	chainHeadHash is not the last in-window receipt
equivocation	fail	Two distinct hashes for one epoch
window-coverage	fail	Gap, overlap, or non-adjacent / non-consecutive windows
unauthenticated-extract	warn	Extract has no verifiable signature; guarantee is conditional
countersign-bad	fail	Present payee countersignature failed verify

Checkpoints SHOULD be registered with a Transparency Service (SHOULD-T11-5). A test deployment MAY use an in-process append-only log as the witness (MAY-T11-6). Cedulon still MUST NOT take custody.

Lifecycle

1. Manifest. Parties sign a Trade Manifest (optional for metered API spend; required for goods with acceptance criteria).
2. Policy check. The adapter submits a structured request to the PDP. Default is deny. An allow is a Decision Token (MUST-T6-4).
3. Payment. On allow, the adapter performs the x402 (or other rail) exchange using exactly the decision fields (MUST-T6-1). The Decision Token is consumed (MUST-T6-2). A reused nonce is denied (MUST-T3-1, MUST-T3-2). A tampered or expired token is denied (MUST-T6-5).
4. Receipt. The Receipt Issuer signs a Spend Receipt. Rail credentials MUST NOT appear in the receipt, logs, or tool results (MUST-T5-2, MUST-T7-1).
5. Dispute Evidence Bundle. If delivery bytes do not match the acceptance-criteria hash, an implementation MUST be able to emit a bundle of manifest + receipt + delivery hash (MUST-T8-3). The bundle MUST NOT be described as an arbitral award or escrow release (MUST-T8-4).

Policy Semantics Policy is default deny. The engine understands three families of rule:

• Limit: maximum amount per payment; maximum cumulative amount per window (MUST-T2-2).
• Velocity: maximum number of allowed payments per window (MUST-T2-1).
• Scope: optional allow-lists for payee, currency, and tool name.

Fail-closed: missing engine, crash, or exception yields deny (MUST-T2-3). Implementations SHOULD emit stable reason codes (SHOULD-T2-5). Decision tokens SHOULD expire after a short TTL (SHOULD-T6-3). The agent-facing spend interface MUST invoke the PDP and MUST NOT expose a parallel ungated rail call to the model (MUST-T5-1).

SCITT Anchoring A Receipt Issuer or relying party MAY construct a SCITT Signed Statement whose payload is either the Spend Receipt COSE object or a privacy profile () and register it with a Transparency Service . The service returns a COSE receipt . Embedding that receipt yields a Transparent Statement. Cedulon does not define a new transparency algorithm.

Privacy Considerations A public transparency encoding MUST support omitting or hashing payer and payee identifiers and MUST support amount redaction or bucket encoding (MUST-T9-1). Implementations MUST NOT write government-ID numbers, payment-instrument PAN, or street address into a public statement (MUST-T9-2). Default public anchors SHOULD publish policyHash, manifestHash, receiptHash, and timestampMs rather than full claims (SHOULD-T9-3). A private auditor MAY receive an unredacted receipt out of band (MAY-T9-4).

Security Considerations This section is authoritative for the protocol requirements in this document. The companion repository file THREAT_MODEL.md is informative and MUST NOT be read as overriding this section.

Prompt injection (T1):

The PDP MUST use structured fields only (MUST-T1-1). Unbound spend MUST be noManifest and still gated (MUST-T1-2). Hosts SHOULD confirm first-use payees (SHOULD-T1-3).

Runaway spend (T2):

Velocity and limits are mandatory (MUST-T2-1, MUST-T2-2). Fail-closed deny on engine fault (MUST-T2-3). Denied attempts MUST NOT count as success (MUST-T2-4).

Replay (T3):

Unique nonce on allow (MUST-T3-1); reuse denied (MUST-T3-2); expired manifest denied (MUST-T3-3); single-use hashed decision (MUST-T3-4). Nonce stores SHOULD persist outside tests (SHOULD-T3-5).

Forgery (T4):

Signed canonical receipts (MUST-T4-1, MUST-T4-2) with the claim set in MUST-T4-3, MUST-T4-4, and MUST-T4-7. Protected-header kid is mandatory (MUST-T4-8). Hash chaining is recommended (SHOULD-T4-5).

Bypass (T5):

Single gated interface (MUST-T5-1). No rail secrets in prompts (MUST-T5-2). Hosts SHOULD isolate the PDP (SHOULD-T5-3).

TOCTOU (T6):

Settlement fields MUST match the six-field decision hash (MUST-T6-1). The allow is a COSE_Sign1 Decision Token (MUST-T6-4) consumed on first use (MUST-T6-2). A failed signature or expired token MUST be rejected (MUST-T6-5).

Key leakage (T7):

Secret key material MUST NOT appear in artifacts (MUST-T7-1). Examples MUST use mock keys (MUST-T7-2). Production SHOULD use an HSM or OS key store (SHOULD-T7-3).

Counterparty (T8):

Manifest bind (MUST-T8-1, MUST-T8-2). Evidence bundle (MUST-T8-3) is not an award (MUST-T8-4). manifestHash is the SHA-256 of the signed COSE bytes (MUST-T8-7). A present payee countersignature MUST verify (MUST-T8-8); absence is allowed (MAY-T8-9).

Privacy (T9):

See .

Rail bypass completeness (T10):

Verifiers MUST reconcile an authenticated extract to receipts with one-to-one ref+amount+currency matching (MUST-T10-1, MUST-T10-6, MUST-T10-7) and MUST fail the audit when any fail-severity finding exists (MUST-T10-4). See .

Checkpoint suppression (T11):

Checkpoints MUST be signed and chained (MUST-T11-1, MUST-T11-4). Totals, count, and chainHeadHash MUST match the half-open window (MUST-T11-2, MUST-T11-7). Equivocation MUST be reported (MUST-T11-3). Continuity and prefix-deletion detection that go beyond the presented chain are conditional on an external transparency witness (MUST-T11-9).

Issuer self-attestation:

A Receipt Issuer that also produces the only copy of the extract can omit settlements. Completeness holds only against an extract the verifier obtained from the rail or from a rail signature.

Key rotation and revocation:

kid identifies the verification key. This -00 does not specify a revocation list. Verifiers MUST pin the issuer keys they accept and MUST stop accepting a kid after an authenticated revocation signal.

Timestamp trust:

timestampMs is issuer-asserted. Window assignment uses that field. A lying issuer can slide a receipt between windows. External timestamping or a transparency log is out of scope for -00.

Collusion:

If the rail operator and the issuer collude, they can publish a matching extract and receipt set that hides a real-world settlement. Cedulon does not detect extract-external agreement.

Reversal, refund, and partial settlement:

State machines for reversal, refund, and partial settlement are out of scope for -00 and are expected in -01.

Optional escrow role Parties MAY name an escrow actor in a Trade Manifest as a third-party role that holds funds under rules outside this protocol (MAY-T8-6). Implementations of this specification MUST NOT take custody or operate escrow (MUST-T8-custody).

IANA Considerations This document has no IANA actions. Private-use CWT labels below -65536 are used so that a registry assignment is not required for -00.

Implementation Status RFC 7942 note: a companion implementation with a runnable verification suite is published at https://github.com/dogrucanemek-alt/cedulon. The code is a profile of this document, not a second specification. This -00 is not an IETF working-group item.

Evolution and Future Work (Informative) This section is a direction, not a commitment. The structures below are reserved in name only. Normative wire formats, tests, and threat-model MUST lines for them belong in later revisions (-01 or -02), written with the same discipline as this -00.

Re-attestation profile Algorithms retire. A Spend Receipt or checkpoint signed under Ed25519 today may need a later verifier that no longer accepts -19. A companion seed sketches re-attestation: register the original COSE bytes as a SCITT Signed Statement and have a current algorithm countersign or receipt them. The principle is that structures outlive ciphers. The first concrete example is the profile's own move from generic EdDSA (-8) to Ed25519 (-19) in .

Streaming reconciliation Epoch checkpoints in this document are batch windows. A later revision (-02) may define a continuous, second-scale profile in which the same completeness relation is evaluated as settlements arrive, without waiting for an epoch close. That work does not change the -00 matching rules.

Generalization Payment is the special case that this -00 implements. The same completeness calculus (an authenticated extract of consumed units reconciled to signed receipts) can apply to other consumable resources such as compute, data, or energy. This document does not specify those profiles.

Informative Notes on Adjacent Protocols x402 uses HTTP 402 to negotiate stablecoin payment. AP2 uses signed mandates as verifiable credentials. Cedulon does not replace either protocol. Profiles built on HTTP Message Signatures authenticate bots; they are not a spend receipt. draft-bates-atp is a lineage neighbor. It does not define rail-extract completeness. draft-vauban-x402-stark-receipts specifies complementary x402 receipt-format variants that a Cedulon Spend Receipt MAY carry as a rail proof; it does not define rail-extract completeness. draft-schrock-ep-outcome-binding compares authorized action bytes to independently observed effects; it does not define rail-extract completeness. draft-marques-asqav-compliance-receipts profiles access-control action receipts (the broader Acta family includes ); it does not define rail-extract completeness. draft-hopley-x402-compliance-receipt records an admission-time compliance decision; it does not define rail-extract completeness.

References Normative References 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. Federal Information Processing Standard, FIPS This document describes elliptic curve signature scheme Edwards-curve Digital Signature Algorithm (EdDSA). The algorithm is instantiated with recommended parameters for the edwards25519 and edwards448 curves. An example implementation and test vectors are provided. 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. CBOR Web Token (CWT) is a compact means of representing claims to be transferred between two parties. The claims in a CWT are encoded in the Concise Binary Object Representation (CBOR), and CBOR Object Signing and Encryption (COSE) is used for added application-layer security protection. A claim is a piece of information asserted about a subject and is represented as a name/value pair consisting of a claim name and a claim value. CWT is derived from JSON Web Token (JWT) but uses CBOR rather than JSON. The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. These design goals make it different from earlier binary serializations such as ASN.1 and MessagePack. This document obsoletes RFC 7049, providing editorial improvements, new details, and errata fixes while keeping full compatibility with the interchange format of RFC 7049. It does not create a new version of the format. Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines the CBOR Object Signing and Encryption (COSE) protocol. This specification describes how to create and process signatures, message authentication codes, and encryption using CBOR for serialization. This specification additionally describes how to represent cryptographic keys using CBOR. This document, along with RFC 9053, obsoletes RFC 8152. Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines a set of algorithms that can be used with the CBOR Object Signing and Encryption (COSE) protocol (RFC 9052). This document, along with RFC 9052, obsoletes RFC 8152. This specification refers to cryptographic algorithm identifiers that fully specify the cryptographic operations to be performed, including any curve, key derivation function (KDF), and hash functions, as being "fully specified". It refers to cryptographic algorithm identifiers that require additional information beyond the algorithm identifier to determine the cryptographic operations to be performed as being "polymorphic". This specification creates fully-specified algorithm identifiers for registered JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) polymorphic algorithm identifiers, enabling applications to use only fully-specified algorithm identifiers. It deprecates those polymorphic algorithm identifiers. This specification updates RFCs 7518, 8037, and 9053. It deprecates polymorphic algorithms defined by RFCs 8037 and 9053 and provides fully-specified replacements for them. It adds to the instructions to designated experts in RFCs 7518 and 9053. CBOR Object Signing and Encryption (COSE) Receipts prove properties of a Verifiable Data Structure (VDS) to a verifier. VDSs and associated Proof Types enable security properties, such as minimal disclosure, transparency, and non-equivocation. Transparency helps maintain trust over time and has been applied to certificates, end-to-end encrypted messaging systems, and supply chain security. This specification enables concise transparency-oriented systems by building on Concise Binary Object Representation (CBOR) and COSE. The extensibility of the approach is demonstrated by providing CBOR encodings for Merkle inclusion and consistency proofs. Traceability in supply chains is a growing security concern. While Verifiable Data Structures (VDSs) have addressed specific issues, such as equivocation over digital certificates, they lack a universal architecture for all supply chains. This document defines such an architecture for single-issuer signed statement transparency. It ensures extensibility and interoperability between different transparency services as well as compliance with various auditing procedures and regulatory requirements. Informative References This document describes a simple process that allows authors of Internet-Drafts to record the status of known implementations by including an Implementation Status section. This will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. This process is not mandatory. Authors of Internet-Drafts are encouraged to consider using the process for their documents, and working groups are invited to think about applying the process to all of their protocol specifications. This document obsoletes RFC 6982, advancing it to a Best Current Practice. The Hypertext Transfer Protocol (HTTP) is a stateless application-level protocol for distributed, collaborative, hypertext information systems. This document describes the overall architecture of HTTP, establishes common terminology, and defines aspects of the protocol that are shared by all versions. In this definition are core protocol elements, extensibility mechanisms, and the "http" and "https" Uniform Resource Identifier (URI) schemes. This document updates RFC 3864 and obsoletes RFCs 2818, 7231, 7232, 7233, 7235, 7538, 7615, 7694, and portions of 7230. This document describes a mechanism for creating, encoding, and verifying digital signatures or message authentication codes over components of an HTTP message. This mechanism supports use cases where the full HTTP message may not be known to the signer and where the message may be transformed (e.g., by intermediaries) before reaching the verifier. This document also describes a means for requesting that a signature be applied to a subsequent HTTP message in an ongoing HTTP exchange. Vauban Research

Acknowledgments Field survey notes and the informative threat-model table in the companion repository helped shape the MUST identifiers used here.

Appendix A. Test Vectors These vectors use RFC 8032 Ed25519 secret scalar #1 (fixture only; never a production key). Hex is lowercase. They MUST match the locked tests in the companion implementation. Receipt COSE_Sign1: Claims: payer=payer-1, payee=payee-1, amount=1, currency=USD, policyHash=aa, manifestHash=null, noManifest=true, x402PaymentRef=null, timestampMs=1700000000000, nonce=n100000000000000, prevReceiptHash=null, outcome=aborted. COSE_Sign1 hex (whitespace ignored; identical to the locked test): Manifest COSE_Sign1: Body: description=fixture-goods, amount=1, currency=USD, acceptanceCriteriaHash=00, cancelCondition=none, expiresAtMs=1700000000000, ap2MandateHash=null. COSE_Sign1 hex (whitespace ignored; identical to the locked test):