The Compliance-Receipt HTTP Response Header Field
draft-singh-psi-http-00

Network Working Group                                           K. Singh
Internet-Draft                                       APEX Infrastructure
Intended status: Informational                           13 October 2026
Expires: 16 April 2027

           The Compliance-Receipt HTTP Response Header Field
                        draft-singh-psi-http-00

Abstract

   This document defines the Compliance-Receipt HTTP response header
   field, a Structured Field that carries a reference to a Proof of
   Stateful Integrity (PSI) receipt for the response.  The signature
   covers every security-relevant parameter.  The header shows that the
   issuer sealed a digest of the response; despite its name it does not
   show that the response, or the service, complies with any law or
   policy.

Status of This Memo

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   This Internet-Draft will expire on 16 April 2027.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Header Field Definition . . . . . . . . . . . . . . . . . . .   2
   3.  Signature Input . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Verification  . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   3
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   Clients that receive machine-generated responses may want a durable,
   independently checkable record that a given response was issued.  The
   key words "MUST", "MUST NOT", "SHOULD", and "MAY" in this document
   are to be interpreted as described in BCP 14 [RFC2119] [RFC8174]
   when, and only when, they appear in all capitals, as shown here.

2.  Header Field Definition

   Compliance-Receipt is a Dictionary Structured Field [RFC9651].
   Members:

   *  v: Integer, version; this document defines 1.

   *  rid: String, receipt identifier.

   *  h: Byte Sequence, SHA-256 of the response content.

   *  st: Token, one of sealed or pending.

   *  kid: String, signing key identifier.

   *  sig: Byte Sequence, Ed25519 signature.

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   All members except sig are REQUIRED.  Unknown members MUST be
   ignored.  A field that fails to parse, repeats a member, or lacks a
   required member MUST be treated as absent.

   Compliance-Receipt: v=1, rid="APEX-NTR-1EEBEA8EE8EBF44A",
     h=:<base64>:, st=sealed, kid="apex-psi-2026", sig=:<base64>:

3.  Signature Input

   The signature input is the serialization, per Section 4.1 of
   [RFC9651], of the Dictionary containing all members other than sig,
   in the order v, rid, h, st, kid.  Signing only rid would allow status
   or digest substitution and is not permitted.  The signature is
   Ed25519 [RFC8032]; keys are discovered from /.well-known/compliance-
   receipt on the issuer origin.

4.  Verification

   A client recomputes SHA-256 of the received content, compares it with
   h, reconstructs the signature input, and verifies sig.  It MAY then
   resolve rid to the full receipt.  Status pending MUST NOT be
   presented as anchored.

5.  Security Considerations

   The header is set by the server; an intermediary able to rewrite
   responses can strip it.  It binds content, not the identity of the
   requester.  Content encodings change bytes; h is over the content as
   received after removing transfer codings but before content decoding.

6.  IANA Considerations

   This document has no IANA actions in this revision.  Registration in
   the Hypertext Transfer Protocol Field Name Registry will be requested
   only if this document advances.

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, May 2017,
              <https://www.rfc-editor.org/info/rfc8174>.

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   [RFC9651]  Nottingham, M. and P-H. Kamp, "Structured Field Values for
              HTTP", RFC 9651, September 2024,
              <https://www.rfc-editor.org/info/rfc9651>.

   [RFC8032]  Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
              Signature Algorithm (EdDSA)", RFC 8032, January 2017,
              <https://www.rfc-editor.org/info/rfc8032>.

7.2.  Informative References

   [PSI]      Singh, K., "Proof of Stateful Integrity (PSI): Signed,
              Merkle-Committed Receipts for Digital Records", Work in
              Progress, Internet-Draft, draft-singh-psi-02, October
              2026, <https://datatracker.ietf.org/doc/draft-singh-psi/>.

Author's Address

   Kawaljeet Singh
   APEX Infrastructure
   Melbourne Victoria
   Australia
   Email: kawaljeet.singh3008@gmail.com
   URI:   https://ai-governance-standard.com

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