Attest verifier

Checks Attest records on this device, with no Attest service: signed agreements, receipts, certificates, Proof Cards and zero-knowledge proofs. Every signature, fingerprint and proof is checked here, and every anchor is read from a public blockchain.

Drop a signed PDF or an evidence file here, or click to choose.
Evidence files (attest-evidence-….json) download from each receipt, certificate, Proof Card and proof page. Add the original file or PDF to check it too. Nothing is uploaded.

Node for the on-chain checks (optional: any node of Horizen works, and every answer is checked against the registries and authority this verifier pins):

How this works

Every fingerprint is SHA-256. Passkey signatures are WebAuthn assertions over the SHA-256 of an exact statement. Issuers sign with P-256 keys: certificates as W3C Verifiable Credentials (JOSE), Proof Cards with selective disclosure (W3C Data Integrity, ecdsa-sd-2023). Zero-knowledge proofs are Groth16 over BN254. Each record, issuer key, revocation and status change is anchored on Horizen, under a value this page recomputes and reads from the chain. The registries are open to anyone, so an anchor counts only when its wallet is one of Attest's: Attest's registry authority registers each one on chain, and this page pins that authority, the registries, the chain, the site where passkeys sign and every circuit's verification key, never taking them from a file it checks. A signed PDF counts only if nothing follows its signed pages but Attest's own attachments. Every format and check is specified in FORMAT.md, so any SHA-256 tool, WebAuthn library, credential library, Groth16 verifier and Ethereum node can repeat them.