Dart

Decrypt MIME using RSAES-OAEP with SHA256 and AES-128 content encryption

See more MIME Examples

Demonstrates how to decrypt MIME what was encrypted with RSAES-OAEP with SHA256 and AES-128 content encryption.

In actuality, we don't really need to know in advance the various algorithms used to encrypt the MIME. When decrypting, the information about the algorithms required are embedded in the PCKS7 message itself, and this tells a decryptor what it should use.

Note: This example requires Chilkat v9.5.0.67 or greater.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // We begin with this encrypted MIME:

  // Content-Type: application/x-pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"
  // someHeader1: Some value 1
  // someHeader2: Some value 2
  // Content-Disposition: attachment; filename="smime.p7m"
  // Content-Transfer-Encoding: base64
  // 
  // MIIDvAYJKoZIhvcNAQcDoIIDrTCCA6kCAQAxggGgMIIBnAIBADB1MGgxCzAJBgNVBAYTAlVTMQsw
  // CQYDVQQIDAJJTDEQMA4GA1UEBwwHV2hlYXRvbjEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQ
  // dHkgTHRkMRcwFQYDVQQDDA5DaGlsa2F0V2lkZ2V0cwIJAMRwugDmvniwMBwGCSqGSIb3DQEBBzAP
  // oA0wCwYJYIZIAWUDBAIBBIIBAFaUL1ga1bOrdqYKcMm+FHUacBvzfBxk0fnPA0AMBdN8BvTWT3CN
  // YuqBhjOGyq0FpYD9pVZybUuFMCVsVyIW2O62HnsOK58YaPEUUcdH2sI+yjqX9UAn0P0nVDSsVdeK
  // W8x9kMfZg+3UP+y1q+lu7VRJO3f2C9oLQpTkc4VW4n7UOcUI0waykLCjCTL8lFDb7/J3GeuMKyhH
  // 5riNz50kpbzqn7m2Ks9yA+QmcTdXclclGFr2vwEUFzSdT2pxh/vaUrogCxkYWbQ2eV7vZg6O4kV0
  // aqHBqySkPTAzHKiHH8K8GVdlTuJ8350CpICa4T8w7/Ht5I7dyOPPKy4C+rVtrvcwggH+BgkqhkiG
  // 9w0BBwEwHQYJYIZIAWUDBAECBBDTC2WNBN+z2I47/4Feu9YqgIIB0MZvl3nC/q/Wzil6HtfQTr12
  // Q5moHY+ORzAa1P9XvX2ZUFhW530mV395mQw/A4o4ekmX9eRPEZquYzZPLT8hNeZIuNdhpcSQUmad
  // rKnKkR0wKJ3jJ3LhOIohVBQSYs8kVDZKq6lJBIznlsurFelZoNEhyRschhteDZx5rb7fCe8c2+/O
  // DHxaqaHCAzm/Bd7kcg6FFfuTZy3tu0PgP5IsXN4OFA3kkvwjAs4XsVS8jdIcmDNBkYieE8WmJOIm
  // Mz7mh/CHWLgWfGKa0Dkb9RcbFgLwYNT3GzuXFw9XPbKkEZjEAtJajWbN6P0WQl96YYd9qZxUpGxZ
  // zjTHEYzViUdUXolfpLufttrRXyxN1RFWhNFMFbv66xYqklMSgpdM/Mbk+EuvX6eXayDPvDBpfYMw
  // NoRAzv1Ony2c0ez9rBemJICicxAzpuvHbRxdjYs63Dnv+TYgpBK12AxWWpPIjXvw0WQKgTC3Tg8s
  // EnuGhpENqso/clJBEBSn4+2WhYtYbdI5sVme67lvqQl1Xxy3r18SWaQbyDOwgYi1E+54lMDOxMy0
  // y0FPHk5pP45DnXWj+XORPp5LhuZr5mf62YOXSSUwR5P0cXy4Rc+pN5lhRQPCf5z2

  final sb = CkStringBuilder();
  final bCrlf = true;
  sb.appendLine('Content-Type: application/x-pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"', bCrlf);
  sb.appendLine('someHeader1: Some value 1', bCrlf);
  sb.appendLine('someHeader2: Some value 2', bCrlf);
  sb.appendLine('Content-Disposition: attachment; filename="smime.p7m"', bCrlf);
  sb.appendLine('Content-Transfer-Encoding: base64', bCrlf);
  sb.appendLine('', bCrlf);
  sb.appendLine('MIIDvAYJKoZIhvcNAQcDoIIDrTCCA6kCAQAxggGgMIIBnAIBADB1MGgxCzAJBgNVBAYTAlVTMQsw', bCrlf);
  sb.appendLine('CQYDVQQIDAJJTDEQMA4GA1UEBwwHV2hlYXRvbjEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQ', bCrlf);
  sb.appendLine('dHkgTHRkMRcwFQYDVQQDDA5DaGlsa2F0V2lkZ2V0cwIJAMRwugDmvniwMBwGCSqGSIb3DQEBBzAP', bCrlf);
  sb.appendLine('oA0wCwYJYIZIAWUDBAIBBIIBAFaUL1ga1bOrdqYKcMm+FHUacBvzfBxk0fnPA0AMBdN8BvTWT3CN', bCrlf);
  sb.appendLine('YuqBhjOGyq0FpYD9pVZybUuFMCVsVyIW2O62HnsOK58YaPEUUcdH2sI+yjqX9UAn0P0nVDSsVdeK', bCrlf);
  sb.appendLine('W8x9kMfZg+3UP+y1q+lu7VRJO3f2C9oLQpTkc4VW4n7UOcUI0waykLCjCTL8lFDb7/J3GeuMKyhH', bCrlf);
  sb.appendLine('5riNz50kpbzqn7m2Ks9yA+QmcTdXclclGFr2vwEUFzSdT2pxh/vaUrogCxkYWbQ2eV7vZg6O4kV0', bCrlf);
  sb.appendLine('aqHBqySkPTAzHKiHH8K8GVdlTuJ8350CpICa4T8w7/Ht5I7dyOPPKy4C+rVtrvcwggH+BgkqhkiG', bCrlf);
  sb.appendLine('9w0BBwEwHQYJYIZIAWUDBAECBBDTC2WNBN+z2I47/4Feu9YqgIIB0MZvl3nC/q/Wzil6HtfQTr12', bCrlf);
  sb.appendLine('Q5moHY+ORzAa1P9XvX2ZUFhW530mV395mQw/A4o4ekmX9eRPEZquYzZPLT8hNeZIuNdhpcSQUmad', bCrlf);
  sb.appendLine('rKnKkR0wKJ3jJ3LhOIohVBQSYs8kVDZKq6lJBIznlsurFelZoNEhyRschhteDZx5rb7fCe8c2+/O', bCrlf);
  sb.appendLine('DHxaqaHCAzm/Bd7kcg6FFfuTZy3tu0PgP5IsXN4OFA3kkvwjAs4XsVS8jdIcmDNBkYieE8WmJOIm', bCrlf);
  sb.appendLine('Mz7mh/CHWLgWfGKa0Dkb9RcbFgLwYNT3GzuXFw9XPbKkEZjEAtJajWbN6P0WQl96YYd9qZxUpGxZ', bCrlf);
  sb.appendLine('zjTHEYzViUdUXolfpLufttrRXyxN1RFWhNFMFbv66xYqklMSgpdM/Mbk+EuvX6eXayDPvDBpfYMw', bCrlf);
  sb.appendLine('NoRAzv1Ony2c0ez9rBemJICicxAzpuvHbRxdjYs63Dnv+TYgpBK12AxWWpPIjXvw0WQKgTC3Tg8s', bCrlf);
  sb.appendLine('EnuGhpENqso/clJBEBSn4+2WhYtYbdI5sVme67lvqQl1Xxy3r18SWaQbyDOwgYi1E+54lMDOxMy0', bCrlf);
  sb.appendLine('y0FPHk5pP45DnXWj+XORPp5LhuZr5mf62YOXSSUwR5P0cXy4Rc+pN5lhRQPCf5z2', bCrlf);

  // Load the encrypted MIME into the MIME object.
  final mime = CkMime();
  mime.loadMimeSb(sb);

  // Provide the required cert + private key from a PFX (.pfx/.p12) file.
  try {
    mime.addPfxSourceFile('qa_data/rsaes-oaep/cert_plus_privatekey.pfx', 'PFX_PASSWORD');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Decrypt.
  try {
    mime.decrypt();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Examine the decrypted MIME.
  print(mime.getMime());
  print('Decrypt test 1 succeeded.');

  // -----------------------------------------------------------
  // Now let's decrypt another way..
  // We have the same cert and private key in PEM files..

  final cert = CkCert();
  cert.loadFromFile('qa_data/rsaes-oaep/cert.pem');

  final privKey = CkPrivateKey();
  privKey.loadPemFile('qa_data/rsaes-oaep/privatekey.pem');

  // Decrypt using the cert + private key
  final mime2 = CkMime();
  mime2.loadMimeSb(sb);

  try {
    mime2.decrypt2(cert, privKey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Examine the decrypted MIME.
  print(mime2.getMime());
  print('Decrypt test 2 succeeded.');
}