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Duplicate openssl pkcs12 –export –in certfile.cer –inkey certfile.key –out certfile.pfx

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How to create a PKCS12 (.p12 or .pfx) from a certificate file and private key file: Demonstrates how to duplicate this OpenSSL command:
Duplicate openssl pkcs12 –export –in certfile.cer –inkey certfile.key –out certfile.pfx

Chilkat React Native Downloads

React Native
import { Cert, CertChain, Pfx, PrivateKey } from '@chilkat/react-native'

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

  const pkey = new PrivateKey();

  // Load the private key from the file.
  try {
    pkey.loadAnyFormatFile('certFile.key', '');
  } catch {
    console.log(pkey.lastErrorText);
    return;
  }

  const cert = new Cert();
  // The LoadFromFile method auto-recognizes the format...
  try {
    cert.loadFromFile('certfile.cer');
  } catch {
    console.log(cert.lastErrorText);
    return;
  }

  // We'll need a cert chain object to create the PKCS12, so get it
  // from the cert.  
  let certChain: CertChain;
  try {
    certChain = cert.getCertChain();
  } catch {
    console.log(cert.lastErrorText);
    return;
  }

  // Create the PFX object, add the cert and private key, and write to a .pfx file.
  const pfx = new Pfx();

  // The cert(s) are automatically added in the call to AddPrivateKey
  try {
    pfx.addPrivateKey(pkey, certChain);
  } catch {
    console.log(pfx.lastErrorText);
    return;
  }

  // Write the .pfx to a file.
  const password = 'myPassword';
  try {
    pfx.toFile(password, 'certfile.pfx');
  } catch {
    console.log(pfx.lastErrorText);
    return;
  }

  console.log('Success.');
}