verifiedby

Quickstart

import { readFileSync } from "node:fs";
import { verify } from "verifiedby";

const bytes = new Uint8Array(readFileSync("contract.pdf"));
const result = await verify(bytes);

console.log(result.status);
// "verified" | "verified-untrusted-root" | "signed-untimed" |
// "unverified" | "mismatch" | "unsupported" | "no-signature"

Runs entirely on the bytes you pass in and crypto.subtle — no network access, no filesystem access beyond what you give it. Node 20+, any modern browser, Deno, or Bun.

What it proves

• Byte-for-byte identity. The file is identical to what was signed or timestamped. Change one byte and it fails.
• Signature validity and chain. The signature over that fact is cryptographically valid, and its certificate chain is intact.
• Proven vs. claimed time. Whether the date is proven by a timestamp authority, or merely claimed by the signer's own software — most tools blur these together.
• How long the proof lasts. Every certificate expires; the result tells you the date after which the file alone can no longer demonstrate its own validity.

What it does not prove

• Who. A document timestamp records when, never who. An ordinary signature proves which certificate was used — a fact about a key, not a verified fact about a person.
• That the document is honest. Nothing here speaks to the sender's identity or the truth of the contents.
• Revocation. Checking that needs network access, which this package deliberately does not take.

Status values

Only mismatch and unverified are failures of the document. Full rubric — what's checked, in what order, and what would have to be true for each verdict to be wrong — is in METHODOLOGY.md.

API surface

verify(pdfBytes, trustAnchors?)

The main entry point. Returns a promise resolving to a result object — see the full field-by-field reference in the README and TypeScript declarations.

extractSignatures(pdfBytes)

The raw signature dictionaries in a PDF — byte ranges, /Contents, /SubFilter — without running verification.

KNOWN_ROOTS

The short, human-checkable list of pinned trust anchors, by public key rather than certificate fingerprint.

registerResolver(resolver) / resolveIdentity(result, pdfBytes)

Attach your own app's identity claims as clearly separate, display-only information — never merged into the cryptographic result, since proof and "a party's records say" are different kinds of evidence.