Dart Requires Chilkat v11.0.0+

Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final bd = CkBinData();
  for (var i = 0; i <= 100; i++) {
    bd.appendEncoded('000102030405060708090A0B0C0D0E0F', 'hex');
  }

  final sha256Base64 = bd.getHash('sha256', 'base64');
  print('sha256 hash in base64 format: $sha256Base64');

  final base64RsaSig = 'AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w==';

  // Get the public key to be used for signature verification.
  final pubKey = CkPublicKey();
  try {
    pubKey.loadFromFile('rsaKeys/chilkat-rsa-2048.pem');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final rsa = CkRsa();
  try {
    rsa.usePublicKey(pubKey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Verify the hash against the signature.
  rsa.encodingMode = 'base64';

  try {
    rsa.verifyHashENC(sha256Base64, 'sha256', base64RsaSig);
    print('Signature valid.');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    print('Signature invalid.');
  }
}