Digital Signatures

Inspect digital signature data embedded in signed PDFs. Requires the full tier.

import { PDFDocument } from "pdfnova";

Read Signatures

const doc = await PDFDocument.open(signedPdf);
const signatures = await doc.getSignatures();

for (const sig of signatures) {
  console.log(`Reason: ${sig.reason}`);
  console.log(`Time: ${sig.signingTime}`);
  console.log(`Filter: ${sig.subFilter}`);
  console.log(`Permissions: ${sig.docMDPPermission}`);
}

SignatureData

Property	Type	Description
index	number	Signature index
contents	Uint8Array	Raw signature bytes (PKCS#7 / CMS)
byteRange	number[]	Byte range of the signed data
subFilter	string	Signature format (adbe.pkcs7.detached, etc.)
reason	string	Stated reason for signing
signingTime	string	Signing timestamp
docMDPPermission	number	Document modification permission level

Format Signature Info

import { SignatureInfo } from "pdfnova";

for (const sig of signatures) {
  console.log(SignatureInfo.formatSummary(sig));
  console.log(SignatureInfo.getSignatureFormat(sig.subFilter));
}

DocMDP Permission Levels

Value	Meaning
1	No changes allowed
2	Form filling and signing allowed
3	Form filling, signing, and annotation allowed

Notes

• pdfnova reads signature data from PDFium but does not perform cryptographic validation. For full verification, extract the contents (PKCS#7 data) and byteRange, then validate using a crypto library like node-forge or the Web Crypto API.
• Signature fields are also visible via doc.getFormFields() with type FormFieldType.Signature.