Dart

RSA Sign using a Private Key on a USB Token or Smartcard

See more Apple Keychain Examples

Create an RSA signature using a private key stored on a USB token or smartcard.

Note: On MacOS and iOS, this example requires Chilkat v10.1.2 or later when the Apple Keychain is used as the underlying means to do the signing.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // 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.
  try {
    cert.loadFromSmartcard('cn=chilkat-rsa-2048');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Signing with 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.
  try {
    rsa.setX509Cert(cert, true);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Sign the SHA-256 hash of the contents of bd.
  final bdSig = CkBinData();
  try {
    rsa.signBd(bd, 'sha256', bdSig);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The RSA signature is equal in length to the size of the RSA key.
  print('Output signature size in bits = ${bdSig.numBytes * 8}');

  // We can save the signature for later verification..
  bdSig.writeFile('rsaSignatures/test1.sig');

  // See the example to verify the RSA signature:
  // Verfies an RSA Signature
}