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Touchstone Verifiable Timestamp (Proof-of-Existence)
x402
Touchstone Verifiable Timestamp (Proof-of-Existence) is a paid API for AI agents from touchstone.locomot.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Binds a SHA-256 digest to a public drand randomness beacon round, producing a trustless anti-backdating receipt proving data existed no earlier than a specific instant.
Price / call$0.001
Success—
StatusUnknown
How this service works
Verifiable timestamp (trustless proof-of-existence / freshness proof): bind a hash to a drand round for an anti-backdating receipt — proves data existed no earlier than a public instant, with no trusted timestamp authority. Privacy: stamp an opaque sha256 digest.
Output
A JSON receipt containing: the operation (stamp/verify), the SHA-256 digest, the drand round number, the UTC time of that round, a 'not_earlier_than' ISO timestamp, a cryptographic beacon proof object, a commitment string, the engine name, whether the result is deterministic given the round, and a human-readable claim string summarizing the proof.
Example use cases
Timestamp intellectual property before filing
“I've got a SHA-256 hash of my design mockups and I need to prove they existed before I submit my patent application — stamp this digest b7e2a1f3c4d5890123456789abcdef0123456789abcdef0123456789abcdef02 to the current drand round so I have a trustless receipt I can use as prior art evidence.”
Anchor contract hash at signing
“We're finalizing a vendor agreement right now and I need a verifiable proof that this contract existed at this exact moment — take this SHA-256 digest c9d3b2e4f5a6901234567890abcdef0123456789abcdef0123456789abcdef03 and bind it to the current drand beacon round so neither party can claim the document was backdated.”
Prove dataset freshness for audit
“Our compliance team needs to verify that the dataset we're submitting for this audit was generated today and not pulled from an older snapshot — stamp this hash d1f4c3e5a6b7012345678901abcdef0123456789abcdef0123456789abcdef04 to the current drand round so auditors have a trustless freshness proof they can independently verify.”
Technical details
Endpoint
GEThttps://touchstone.locomot.io/timestampWhen to prefer
Use this endpoint when you need a trustless, privacy-preserving proof that data existed at or before a specific moment in time, without relying on any centralized timestamp authority. Ideal for intellectual property protection, contract timestamping, audit trails, and freshness proofs where the input can be kept private as an opaque hash. Prefer over blockchain-based timestamping when low cost, speed, and privacy (no on-chain data) matter.
Side effects
- Invalid or malformed SHA-256 hex digest (not 64 hex characters) returns an error
- Verify operation called without a round parameter fails with missing parameter error
- Provided round number does not exist yet or is in the future — beacon not yet available
- Both data and hash provided simultaneously may cause ambiguity or rejection
- Network unavailability of drand beacon causes service failure
- Round number integer out of valid range returns an error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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