node-signpdf

node-signpdf

Simple signing of PDFs in node.

Usage

See Signing PDF in simple steps

Notes

• The process of signing a document is described in the Digital Signatures in PDF document.

• This lib:

  • requires the signature placeholder to already be in the document. Takes Buffers of the PDF and a P12 certificate to use when signing
  • does not cover multiple signatures, incremental updates, etc. Only the basic scenario of signing a freshly created PDF.

Signing PDF in simple steps

Generate a PDF

In the test PDFKit is used for generating the PDF. This also allows easy addition of the signature placeholder.

Append a signature placeholder

What's needed is a Sig element and a Widget that is also linked in a Form. The form needs to be referenced in the root descriptor of the PDF as well. A readable sample is available in the test.

Generate and apply signature

That's where node-signpdf kicks in. Given a PDF and a P12 certificate a signature is generated in detached mode and is replaced in the placeholder. This is best demonstrated in the tests.

Dependencies

node-forge is used for working with signatures.

PDFKit is used in the tests for generating a PDF with a signature placeholder.

Credits

The whole signing flow is a rework of what's already in pdfsign.js so thanks go to @tbocek