React Native

RSA Sign an Encoded Hash

See more RSA Examples

Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex). React Native

import { BinData, Cert, Rsa } from '@chilkat/react-native'

function chilkatExample() {
  let success = false;

  // Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
  // this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

  // Chilkat automatically detects and determines the way in which the HSM is used,
  // which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

  const cert = new Cert();

  // Set the token/smartcard PIN prior to loading.
  cert.smartCardPin = '123456';

  // Specify the certificate by its common name.
  success = true;
  try {
    cert.loadFromSmartcard('cn=chilkat-rsa-2048');
  } catch {
    success = false;
  }
  if (!success) {
    console.log(cert.lastErrorText);
    return;
  }

  console.log(`Signing with the private key for this cert: ${cert.subjectCN}`);

  // Create data to be hashed and signed.
  const bd = new BinData();
  for (let i = 0; i <= 100; i++) {
    bd.appendEncoded('000102030405060708090A0B0C0D0E0F', 'hex');
  }

  const rsa = new Rsa();

  // Use the certificate's private key for signing.
  success = true;
  try {
    rsa.setX509Cert(cert, true);
  } catch {
    success = false;
  }
  if (!success) {
    console.log(rsa.lastErrorText);
    return;
  }

  // We'll first compute the hash and then pass the encoded hash to be signed.
  const sha256Base64 = bd.getHash('sha256', 'base64');
  console.log(`sha256 hash in base64 format: ${sha256Base64}`);

  // Pass in the base64 hash and return a base64 signature.
  rsa.encodingMode = 'base64';
  const rsaSigBase64 = rsa.signHashENC(sha256Base64, 'sha256');
  if (!success) {
    console.log(rsa.lastErrorText);
    return;
  }

  console.log(`RSA signature as base64: ${rsaSigBase64}`);
}