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Hermes Notar – SHA-256 Digest Timestamping & Notarization
x402
Hermes Notar – SHA-256 Digest Timestamping & Notarization is a paid API for AI agents from notar.185-190-142-134.sslip.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-31).
Submit a SHA-256 hash of any content to receive a Nostr-signed receipt and a Bitcoin-anchored OpenTimestamps proof of existence at a specific moment in time.
Price / call$0.001
Success—
StatusUnknown
How this service works
Send a SHA-256 digest of your output. Get an instant Nostr-signed receipt and a Bitcoin-anchored OpenTimestamps proof that anyone can verify without trusting us. Use it as proof of delivery, proof of authorship, or audit trail (e.g. EU AI Act logging).
Output
The agent receives a Nostr-signed receipt confirming the digest was recorded, plus an OpenTimestamps (OTS) proof file anchored to the Bitcoin blockchain. Both artifacts allow any third party to independently verify that the submitted SHA-256 hash existed at the attested moment without relying on the service provider.
Example use cases
EU AI Act compliance logging
“I need to notarize the SHA-256 hash of every AI-generated decision my system produces today — can you submit this hash 'b9d2e7f1c3a4...88cc' and get me a Bitcoin-anchored timestamp and Nostr receipt I can store in our compliance audit log?”
Proof of authorship for creative work
“I just finished writing a whitepaper and want to prove I authored it before publishing — please timestamp the SHA-256 digest '4f8a1c3e9d2b...77ff' on Bitcoin via Notar so I have a cryptographic receipt showing it existed right now.”
Tamper-evident proof of delivery
“Before I send this contract to the client, notarize its SHA-256 hash 'c7e3a9b1d4f2...55ee' so I have an OpenTimestamps proof and a Nostr-signed receipt that can serve as verifiable proof of delivery at this exact moment.”
Technical details
Endpoint
GEThttps://notar.185-190-142-134.sslip.io/x402/earn/match?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a decentralized, independently verifiable proof of existence for any content hash — especially for regulatory compliance (EU AI Act), proof of authorship, or tamper-evident audit trails. Prefer this over centralized timestamping services when the verifier must not need to trust the notary, since both the Nostr receipt and OTS proof are self-verifiable. It is ideal for AI agents that must log outputs with cryptographic accountability at minimal cost ($0.001 per call).
Side effects
- Missing or malformed SHA-256 digest returns a 400 Bad Request
- Payment not fulfilled via x402 protocol returns a 402 Payment Required
- Bitcoin network congestion may delay final blockchain confirmation (OTS proof pending state)
- Invalid digest format (not 64-character hex) results in validation error
- Service temporarily unavailable returns 503 with no receipt issued
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"results": [
{
"url": "https://...",
"title": "...",
"platform": "OpenTask",
"usd_effective": 1
}
]
}
}Tags
x402
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