Dart

RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format. 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 a string to be hashed and signed.
  final sb = CkStringBuilder();
  final crlfLineEnding = true;
  for (var i = 0; i <= 10; i++) {
    sb.appendLine('This is a test.', crlfLineEnding);
  }

  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 utf-8 byte representation of the contents of sb
  // Return the signature in base64 format.
  rsa.encodingMode = 'base64';
  rsa.charset = 'utf-8';
  final stringToSign = sb.getAsString();
  final String sigBase64;
  try {
    sigBase64 = rsa.signStringENC(stringToSign, 'sha256');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('RSA signature as base64: $sigBase64');
}