Three steps. Zero trust required.
The service never sees your file and never touches your keys.
Sign
You hash your document and sign the hash on your own device. Only the hash, signature, and public key are sent — never the content.
Anchor
The service verifies the signature and writes a canonical proof to a BSV OP_RETURN, returning a self-contained certificate.
Verify
Anyone re-checks the signature offline and confirms the anchor against BSV block headers — no NotaryHash server, no database, no trust in us.
Built to be believed in 20 years.
Privacy by construction
The document and your private key never leave your machine. We physically cannot leak what we never receive.
Post-quantum ready
Classical ECDSA plus ML-DSA (FIPS 204) and SLH-DSA (FIPS 205) — 16 signature algorithms, so proofs survive the quantum transition.
Trustless verification
Certificates carry an SPV proof. Verify the anchor against block headers alone — the chain is the trust anchor, not our server.
Merkle batching
Many proofs anchor under a single transaction via an RFC 6962 Merkle root, driving per-proof cost toward zero at volume.
Deterministic proofs
The integrity root is a fixed, length-prefixed binary encoding — never JSON — so any implementation in any language reproduces identical bytes.
Time from the chain
The proof-of-existence time comes from the block that holds the anchoring transaction, not a server clock: the signed hash existed by about that block’s time. It is not the time of signing.
Verify a certificate
Paste a NotaryHash certificate to check it now. Certificates with an SPV envelope are verified against BSV block headers.
A simple API. Open verification.
REST endpoints with OpenAPI docs at /docs. Verification is open to everyone; anchoring requires an API key. You sign locally — only the hash, signature, and public key are ever sent.
# Supported algorithms (classical + post-quantum)
curl https://notaryhash.com/v1/algorithms
# Verify a certificate — offline checks + SPV anchor against block headers
curl -X POST https://notaryhash.com/v1/verify \
-H 'Content-Type: application/json' \
-d '{ "certificate": { /* paste a certificate */ } }'
# Anchor a signed hash (needs X-API-Key; the document never leaves your machine)
curl -X POST https://notaryhash.com/v1/notarize \
-H 'Content-Type: application/json' -H 'X-API-Key: YOUR_KEY' \
-d '{ "algorithm": "ECDSA-secp256k1", "payloadHash": "<sha256-hex>",
"publicKey": "<hex>", "signature": "<hex>" }'
Next-generation trust infrastructure
NotaryHash is part of SmartLedger's post-quantum blockchain, identity, and AI stack for enterprise and government.
NotaryHash™
Blockchain notarization for records and audit trails.
NotaryChain™
Air-gapped, post-quantum hashchain for governments and enterprises — append-only, tamper-evident, ML-DSA-signed, with node replication.
GovHash™
Post-quantum-ready attestation for public institutions.
OriginNeural™
Auditable agentic AI with provenance tracking.
AI Script Protocol™
Notarized media creation with IP protection.