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PDF-SDK
Signatures

Sign PDFs inside your app

Handwritten signatures for everyday approvals, and cryptographic digital signatures when a document has to prove who signed it and that it has not changed since.

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Handwritten and digital PDF signatures.

  • Handwritten signatures

    Users draw a signature and place it on the page, like signing on paper.

  • Digital signatures

    Sign with a digital ID: an RSA-2048 key and an X.509 certificate, written as a detached PKCS#7 (CMS) signature.

  • Visible or invisible

    Show the signature in a corner of a page you choose, or sign without a visible mark.

  • Counter-signing

    Signing appends to the file, so earlier signatures stay valid and a second person can sign the same document.

  • Keys stay yours

    The private key never enters the library. On the web the ID’s key cannot leave the browser; with an HSM, a remote signer or a hardware token, plug in your own signer.

  • Reason and location

    Record why and where a document was signed, alongside the signer and the time.

From your code.

Creates (or reuses) a digital ID in the browser and signs the current page.

See the API reference 
import { createDigitalId, loadDigitalId, signDocument } from '@pdfsdk/editor';

const id = (await loadDigitalId())
  ?? (await createDigitalId({ name: 'Ada Lovelace' }));
const { bytes } = await signDocument(editor, pdf, id, {
  reason: 'I approve this document',
  placement: 'bottom-right',
  pageIndex: editor.activePage,
  pageSize: editor.pageSizePoints(editor.activePage)!,
});

Available on

Used in

Signatures questions.

A handwritten signature is a drawing placed on the page. A digital signature is cryptographic: it identifies the signer by a certificate and shows whether the document changed after signing.

Yes. The private key never enters the library; supply your own signer and the SDK lays out and writes the signature.

Yes. Each signature is appended, so earlier signatures stay valid and the same call counter-signs.

Related features

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