@embedpdf/plugin-signature

Document-scoped digital signing for EmbedPDF: sign a signature field with a mark (a stamp-library asset — drawn, typed, uploaded — or bytes you bring) through a signer port you configure; fill a field visually without sealing; validate what is signed; and drop an armed mark onto a field.

The plugin owns the act and nothing else:

• marks are the stamp plugin's (@embedpdf/plugin-stamp) — one library of kind signatures per person, holding a signature asset and optional initials;
• the key is a SignerPort from @embedpdf/core-signature (webCryptoSigner, remoteSigner, personalSigner), the key setting, resolved per signing;
• the engine draws the mark's page into the field and seals the bytes (doc.signatures.prepare → CMS → complete); on the cloud the server publishes the new version.

import { toFieldRef } from '@embedpdf/plugin-form';
import {
  signaturePlugin,
  SignatureToken,
  personalSigner,
  indexedDbKeyStore,
} from '@embedpdf/plugin-signature';

signaturePlugin({
  key: () => personalSigner({ subject: 'Ada Lovelace', store: indexedDbKeyStore('keys') }),
  trust: { anchors: async () => [rootCertificateDer] },
  mode: 'sign', // 'sign' (the default with a key) | 'visual' (the default without) | 'ask'
});

const signature = ctx.get(SignatureToken);
await signature.placeMark({ assetId }, { field: toFieldRef('approval') }); // sign / fill / ask, by mode
await signature.placeMark({ assetId }, { page, center: { x: 120, y: 90 } }); // elsewhere: a stamp

With the interaction hub and the stamp plugin present, a mark armed from a signatures library and clicked over an unsigned signature field goes into the field; anywhere else it is placed as a stamp.

Requires @embedpdf/plugin-form; optional @embedpdf/plugin-stamp, @embedpdf/plugin-annotation, @embedpdf/plugin-interaction. See the docs page headless/forms/signatures for the full contract.