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Open specification

RCR/1 receipt format.

RCR/1 is a draft JSON receipt profile for cryptographic proof records. RANKIGI is the reference implementation, not a standards body.

Draft status

Published for review. Do not treat RCR/1 as an independent industry standard.

rcr-receipt.json
{
  "receipt_id": "rcr_01hx...",
  "subject": {
    "agent_id": "agt_418e2d1c",
    "action_type": "tool_call"
  },
  "hashes": {
    "canonical_payload": {
      "alg": "sha256",
      "value": "3e2b0ab0..."
    },
    "previous_receipt": {
      "alg": "sha256",
      "value": "b071e8d1..."
    }
  },
  "integrity": {
    "sig_alg": "ed25519",
    "timestamp": "2026-06-04T03:14:15.926Z"
  }
}

What it defines

Canonical payload hash

Stable bytes first. RCR/1 defines the digest that verifiers recompute.

Previous receipt hash

Receipts can point to the prior receipt, creating a tamper-evident sequence.

Signature metadata

Receipts carry the signing algorithm and key identifier needed for verification.

Caveats

Each receipt states what it proves and what it does not prove.