API Quickstart

This path is for teams integrating Trusted Signatures directly into existing PDF generation systems.

1. Endpoint

Method: POST
URL: https://api.trusted-signatures.com/v1/sign
Content-Type: application/json

2. Request shape

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{
  "digestAlgorithm": "SHA256",
  "digest": "<base64-pdf-digest>"
}

3. Authentication headers

X-Authorization-Algorithm: HmacSHA256
X-Authorization-Time: current UTC ISO-8601
X-Authorization-Key: your API key ID
X-Authorization: base64 HMAC over raw_body + X-Authorization-Time

4. Expected success response

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{
  "signature": "<base64-cms>"
}

signature is the CMS/PKCS#7 payload to embed into your PDF /Contents placeholder.

Copy/Paste Example (Node.js)

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import crypto from "node:crypto";

const body = JSON.stringify({
  digestAlgorithm: "SHA256",
  digest: process.env.PDF_DIGEST_B64,
});

const authTime = new Date().toISOString();
const authorization = crypto
  .createHmac("sha256", Buffer.from(process.env.TS_API_KEY, "hex"))
  .update(body + authTime, "utf8")
  .digest("base64");

const res = await fetch("https://api.trusted-signatures.com/v1/sign", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-Authorization-Algorithm": "HmacSHA256",
    "X-Authorization-Time": authTime,
    "X-Authorization-Key": process.env.TS_API_KEY_ID,
    "X-Authorization": authorization,
  },
  body,
});

if (!res.ok) throw new Error(await res.text());
const data = await res.json();
console.log(data.signature);

Minimal Sealing Flow

Build a PDF signature placeholder (recommended ~34 KB).
Compute SHA-256 digest over PDF byte range.
Call POST /v1/sign.
Decode base64 CMS response.
Embed CMS bytes into /Contents and pad remaining bytes with 00.
Save PDF and validate in Acrobat/Reader.

Error handling

Common status codes:

400: invalid body or headers
401: auth failure
403: request blocked
413: payload too large
500: server error

Next steps

Need local pipeline tooling? Use the CLI quickstart.
Need architecture review for rollout and controls? Book demo.

PDF Signing API

Ship faster with predictable trust behavior