# HALOWERK sicherwerk RFC 3161 Timestamp Request Builder

> HALOWERK sicherwerk RFC 3161 Timestamp Request Builder is a paid API for AI agents from sicher.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-30).

Builds a ready-to-post RFC 3161 TimeStampReq binary from a SHA-256 digest, including nonce and certificate request flag, using a pinned OpenSSL build.

## Facts

- Endpoint: POST https://sicher.halowerk.com/v1/oss-openssl-rfc3161-request-build?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-sicherwerk-rfc-3161-timestamp-request-builder-471f761b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qfxoDOWT7tul509Az_kcT

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 halowerk-sicherwerk-rfc-3161-timestamp-request-builder-471f761b -d '<json body>'
```

Example prompt: Build me an RFC 3161 timestamp request for the SHA-256 digest a3f1c2d4e5b6789012345678abcdef1234567890abcdef1234567890abcdef12 — include a fresh nonce and ask the TSA to attach its signing certificate.

## When to prefer this

Choose this endpoint when you need a cryptographically correct, nonce-protected RFC 3161 timestamp request binary built by a deterministic pinned OpenSSL build, rather than constructing the ASN.1 structure yourself. It is ideal when you want the TSA to include its signing certificate in the reply (for chain verification) and when you need the message imprint echoed back for integrity confirmation. Prefer this over generic TSA client libraries when reproducibility and a pinned build are important for audit or compliance purposes.

## Known failure modes

- Invalid or malformed SHA-256 hex string (not exactly 64 hex characters) — returns validation error
- Payment failure or insufficient USDC balance via x402 — request not processed
- Internal OpenSSL encoding error — returns server error
- Missing sha256 field in request body — returns schema validation error

## How this service works

Produces a ready-to-post RFC 3161 TimeStampReq for a SHA-256 digest you already computed. The pinned OpenSSL build encodes the message imprint, adds a fresh nonce so a replayed response can be detected, and sets the flag that asks the timestamp authority to include its signing certificate in the reply. The result is returned as a binary artifact together with the imprint it was built around, so the caller can check that the request really covers the intended digest.

## Output

A DER-encoded RFC 3161 TimeStampReq binary artifact ready to POST to a timestamp authority, along with the message imprint it was built around (so the caller can confirm the request covers the intended digest). The request includes a fresh random nonce to detect replayed TSA responses and the certReq flag set to true so the TSA includes its signing certificate in the reply.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "sha256": {
   "type": "string",
   "pattern": "^[a-fA-F0-9]{64}$"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-sicherwerk-rfc-3161-timestamp-request-builder-471f761b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sicher.halowerk.com](https://www.zero.xyz/host/sicher.halowerk.com/llms.txt)