# Securaw TimeChain2 SHA-256 Bitcoin Proof Verification

> Securaw TimeChain2 SHA-256 Bitcoin Proof Verification is a paid API for AI agents from www.securaw.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-18).

Verifies a SHA-256 hash against a Securaw/TimeChain2 event, reporting both registry checks and direct-file Bitcoin timestamp proof separately with downloadable proof when available.

## Facts

- Endpoint: POST https://www.securaw.com/cryptovar/x402/proof_verify?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/securaw-timechain2-sha-256-bitcoin-proof-verification-18118d8c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kkYB2KSZU8q54W_onoJe7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability securaw-timechain2-sha-256-bitcoin-proof-verification-18118d8c -d '<json body>'
```

Example prompt: Can you check whether my file with SHA-256 hash 3a7bd3e2360a3d29eea436fcfb7e44c735d117c42d1c1835420b6b9942dd4f1b was confirmed on Bitcoin using Securaw/TimeChain2 event ID DOC-2024-INVOICE-001?

## When to prefer this

Choose this endpoint when you need to cryptographically verify that a specific file's SHA-256 hash is anchored to the Bitcoin blockchain via a Securaw/TimeChain2 event, particularly when you need the distinction between a registry-level check and a direct-file Bitcoin proof, or when you need to download a proof artifact. Not suitable for verifying timestamps on arbitrary blockchains, general hash lookup without a TimeChain2 event ID, or non-Bitcoin proof systems.

## Known failure modes

- Event ID not found — billable result returned indicating missing event
- SHA-256 mismatch between supplied hash and event record — billable mismatch result
- Proof status is pending or unavailable — not Bitcoin confirmed, clearly flagged
- Legacy receipt without direct-file proof — identified explicitly in response
- Invalid SHA-256 format (not 64 lowercase hex chars) — validation error
- Invalid event_id format — validation error
- Missing Idempotency-Key header — request rejected
- Payment failure or insufficient USDC balance — 402 payment required

## How this service works

Check a SHA-256 against a Securaw/TimeChain2 event. Reports registry checks and direct-file Bitcoin proof separately, with downloadable proof when available. Missing events and mismatches are billable results. Pending/unavailable is NOT Bitcoin confirmed. Legacy receipts without direct-file proofs are explicitly identified. No arbitrary-chain verification. Idempotency-Key required.

## Output

Returns a structured result distinguishing registry-level checks from direct-file Bitcoin proof confirmation, indicates whether a proof is downloadable, flags mismatches between the provided SHA-256 and the event record, explicitly identifies legacy receipts lacking direct-file proofs, and clarifies that pending or unavailable statuses are not Bitcoin-confirmed. Missing events and mismatches are billable results.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "service": {
   "enum": [
    "proof_verify"
   ],
   "type": "string"
  },
  "parameters": {
   "type": "object",
   "title": "VerifyInput",
   "required": [
    "sha256",
    "event_id"
   ],
   "properties": {
    "sha256": {
     "type": "string",
     "title": "Sha256",
     "pattern": "^[0-9a-f]{64}$",
     "description": "Lowercase SHA-256 of exact original bytes, computed locally. No filename or private content."
    },
    "event_id": {
     "type": "string",
     "title": "Event Id",
     "pattern": "^[A-Za-z0-9][A-Za-z0-9_-]{0,127}$",
     "description": "Securaw/TimeChain2 event identifier from a receipt, never a URL."
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/securaw-timechain2-sha-256-bitcoin-proof-verification-18118d8c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.securaw.com](https://www.zero.xyz/host/www.securaw.com/llms.txt)