React Native Requires Chilkat v11.0.0+

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. React Native

import { Cert, PrivateKey, PublicKey, Rsa } 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 privKey = new PrivateKey();

  // Load the private key from an RSA .key file:
  try {
    privKey.loadPemFile('privateKey.key');
  } catch {
    console.log(privKey.lastErrorText);
    return;
  }

  const rsa = new Rsa();

  // Import the private key into the RSA component:
  try {
    rsa.usePrivateKey(privKey);
  } catch {
    console.log(rsa.lastErrorText);
    return;
  }

  // Create the signature as a hex string:
  rsa.encodingMode = 'hex';

  const strData = 'This is the string to be signed.';

  // Sign the string using the sha256 hash algorithm.
  // Other valid choices are "md2", "sha1", "sha384",
  // "sha512", and "md5".
  const hexSig = rsa.signStringENC(strData, 'sha256');

  console.log(hexSig);

  // Load a digital certificate from a .cer file:
  const cert = new Cert();

  try {
    cert.loadFromFile('myCert.cer');
  } catch {
    console.log(cert.lastErrorText);
    return;
  }

  const pubKey = new PublicKey();
  cert.getPublicKey(pubKey);

  // Now verify using a new instance of the RSA object:
  const rsa2 = new Rsa();

  // Import the public key into the RSA object:
  try {
    rsa2.usePublicKey(pubKey);
  } catch {
    console.log(rsa2.lastErrorText);
    return;
  }

  // The signature is a hex string, so make sure the EncodingMode is correct:
  rsa2.encodingMode = 'hex';

  // Verify the signature:
  try {
    rsa2.verifyStringENC(strData, 'sha256', hexSig);
  } catch {
    console.log(rsa2.lastErrorText);
    return;
  }

  console.log('Success.');
}