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COSE Receipts / Merkle Tree Proofs with CCF — draft-ietf-cose-merkle-tree-proofs, draft-ietf-scitt-receipts-ccf-profile#

IETF 122 (Bangkok) digest Program Wildcard pick Bangkok · 15–21 March 2025

  • Tier: Wildcard
  • Why: A genuinely different trust primitive from certificates: instead of "a CA vouches for this key," a verifiable-ledger receipt proves "this statement was logged, at this point, tamper-evidently" — the same shape of guarantee Certificate Transparency gives certs, generalized to arbitrary signed statements.
  • What: cose-merkle-tree-proofs (COSE Receipts) proves properties of a verifiable data structure to a verifier — minimal disclosure, transparency, non-equivocation — via CBOR encodings of Merkle inclusion and consistency proofs. receipts-ccf-profile profiles this specifically for logs produced by Microsoft's Confidential Consortium Framework (CCF), a TEE-backed ledger, for stronger tamper-evidence guarantees. (from abstract only)
  • How: A transparency service appends a signed statement to a Merkle-tree-backed log and returns a receipt (an inclusion proof) that any relying party can verify offline against the log's published root, without trusting the service itself beyond its published commitments.
  • Where applicable: Currently narrow (CCF-specific profile), but the underlying COSE Receipts mechanism is designed to generalize — it's the proof format underneath SCITT (Core, above) and worth understanding as transparency-ledger patterns spread beyond certificates.