Dart

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). Dart

import 'package:chilkat/chilkat.dart';

void main() {
  var 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.

  final cert = CkCert();

  // 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');
  } on ChilkatException {
    success = false;
  }
  if (!success) {
    print(cert.lastErrorText);
    return;
  }

  print('Signing with the private key for this cert: ${cert.subjectCN}');

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

  final rsa = CkRsa();

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

  // We'll first compute the hash and then pass the encoded hash to be signed.
  final sha256Base64 = bd.getHash('sha256', 'base64');
  print('sha256 hash in base64 format: $sha256Base64');

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

  print('RSA signature as base64: $rsaSigBase64');
}