Notarize a document or data hash for AI agents: submit a SHA-256 hash (or short content hashed server-side) and get a timestamped, Ed25519-signed proof-of-existence receipt, verifiable offline with no callback. Prove an artifact, agent output or decision existed at a point in time. Honest scope: this is a SIGNED proof-of-existence receipt, NOT a blockchain-anchored or eIDAS/RFC-3161 legal timestamp. The issuer never sees your content when you send only a hash.

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