Apex PSI · Notarisation
Seal
Hash, canonicalise and sign any artefact entirely inside your browser. No account, no upload, no server. You leave with a receipt that verifies without this site.
Content
Drop a file, or click to choose
Any file type, any size. The bytes are streamed through SHA-256 locally in 4 MB chunks and never leave this device.
SHA-256 (hash-wasm, streamed) · RFC 8785 canonical JSON · Ed25519 (@noble/ed25519). The signing key is generated in this tab and is never transmitted.
Receipt
Nothing sealed yet. Choose a file or paste text, then seal. The result appears here and downloads as a .praman file containing the digest, the canonicalisation method, the timestamp, the issuer, the predicates, the verify URL and the Ed25519 signature.
Seal into the live ledger
This writes a real, public entry to the APEX PSI ledger: a canonical digest, a Merkle leaf, an Ed25519 signature and a post-quantum signature. The record cannot be edited or removed afterwards.
A ledger entry proves these exact bytes were recorded at this time. It makes no claim that the statement is true.
Local seal vs ledger seal
The panel above your left seals in your browser: nothing is uploaded and the receipt verifies offline forever. The ledger seal writes a public entry to the APEX PSI ledger, which is what you want when a third party — a regulator, a counterparty, a court — has to be able to find the record without you.
Ledger entries are Merkle-batched and anchored to Bitcoin. Once anchored, no one, including us, can alter or withdraw them.