Integrity and timing of canonical artefacts are proven by SHA-256 fingerprints anchored through OpenTimestamps into the Bitcoin blockchain, with receipts held on file. The AI Constitution's artefact is anchored in block 917510 and later blocks; the v1.0 public releases in block 937474. Plaintext is never written on-chain.
Proof of existence is the mechanism by which the framework demonstrates that a canonical artefact existed no later than a given time: its SHA-256 digest is anchored through OpenTimestamps into the Bitcoin blockchain, and the receipts are held on file for verification.
A fingerprint proves integrity; an anchor proves timing. Together they give an "existence as of" posture that is independent of any institution's say-so.
The evidence pipeline is export, SHA-256 digest, ledger timestamp, Evidence Locker, Package Index. No plaintext is placed on public ledgers. The public releases of v1.0 are anchored in block 937474, attesting existence no later than 2026-02-20. The Constitution's archival artefact carries its own digest, anchored in blocks 917510, 917515 and 917582, and referenced inside the public copy's provenance notice.
An anchor proves that bytes with this digest existed at that time. It does not prove authorship, correctness or official status; official status comes from the docket.