Verify a sealed record.

Paste or drop a Five × Five receipt below. This page recomputes the SHA-256 and checks the Ed25519 signature in your own browser: no server, no access to any private key, and nothing you paste leaves this device. Alter a single character of the record and the signature fails.

Or verify it offline, in Node

npm i tweetnacl   # then, in the folder with fivexfive-receipt.json:
node -e "const n=require('tweetnacl'),r=require('./fivexfive-receipt.json');console.log(n.sign.detached.verify(Buffer.from(r.message),Buffer.from(r.signature,'base64'),Buffer.from(r.publicKey,'base64'))?'VALID':'TAMPERED')"

Five × Five · a GNOSIS product · the seal is math, not opinion.
Demo receipts are signed with a per-session browser key, which proves integrity. Production keys live in AWS KMS/CloudHSM in Canada and only the public key is published, which adds provenance. · back to the MVP