React Native

Get PDF Signer Certs

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get React Native

import { Cert, JsonObject, Pdf } from '@chilkat/react-native'

function chilkatExample() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  const pdf = new Pdf();

  // Load a PDF that has cryptographic signatures to be validated
  try {
    pdf.loadFile('qa_data/pdf/sign_testing_1/helloSigned2.pdf');
  } catch {
    console.log(pdf.lastErrorText);
    return;
  }

  // Each time we verify a signature, information about the signature is written into
  // sigInfo (replacing whatever sigInfo previously contained).
  const sigInfo = new JsonObject();

  // Iterate over each signature and validate each.
  const numSignatures = pdf.numSignatures;
  let validated = false;
  const cert = new Cert();
  let i = 0;
  while (i < numSignatures) {
    validated = true;
    try {
      pdf.verifySignature(i, sigInfo);
    } catch {
      validated = false;
    }
    console.log(`Signature ${i} validated: ${validated}`);

    // After calling VerifySignature, you can get the signer certificate by calling
    // GetSignerCert with the same index. 
    try {
      pdf.getSignerCert(i, cert);
      console.log(`PDF signer certificate: ${cert.subjectDN}`);
    } catch {
      // pdf.getSignerCert() failed; continue anyway.
    }

    i++;
  }

  console.log('Finished.');
}