Dart Requires Chilkat v11.0.0+

JWE using RSAES-PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256

See more JSON Web Encryption (JWE) Examples

This example duplicates the example A.2 in RFC 7516 for JSON Web Encryption (JWE). 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.

  // Note: This example requires Chilkat v9.5.0.66 or greater.

  final plaintext = 'Live long and prosper.';

  // First build the JWE Protected Header.
  // We want to build this: {"alg":"RSA1_5","enc":"A128CBC-HS256"}
  final jweProtHdr = CkJsonObject();
  jweProtHdr.appendString('alg', 'RSA1_5');
  jweProtHdr.appendString('enc', 'A128CBC-HS256');
  print('JWE Protected Header: ${jweProtHdr.emit()}');
  print('--');

  // The specific RSA key used in the A.2 example is the following JWK:
  final sbJwk = CkStringBuilder();
  sbJwk.append('{"kty":"RSA",');
  sbJwk.append('"n":"sXchDaQebHnPiGvyDOAT4saGEUetSyo9MKLOoWFsueri23bOdgWp4Dy1Wl');
  sbJwk.append('UzewbgBHod5pcM9H95GQRV3JDXboIRROSBigeC5yjU1hGzHHyXss8UDpre');
  sbJwk.append('cbAYxknTcQkhslANGRUZmdTOQ5qTRsLAt6BTYuyvVRdhS8exSZEy_c4gs_');
  sbJwk.append('7svlJJQ4H9_NxsiIoLwAEk7-Q3UXERGYw_75IDrGA84-lA_-Ct4eTlXHBI');
  sbJwk.append('Y2EaV7t7LjJaynVJCpkv4LKjTTAumiGUIuQhrNhZLuF_RJLqHpM2kgWFLU');
  sbJwk.append('7-VTdL1VbC2tejvcI2BlMkEpk1BzBZI0KQB0GaDWFLN-aEAw3vRw",');
  sbJwk.append('"e":"AQAB",');
  sbJwk.append('"d":"VFCWOqXr8nvZNyaaJLXdnNPXZKRaWCjkU5Q2egQQpTBMwhprMzWzpR8Sxq');
  sbJwk.append('1OPThh_J6MUD8Z35wky9b8eEO0pwNS8xlh1lOFRRBoNqDIKVOku0aZb-ry');
  sbJwk.append('nq8cxjDTLZQ6Fz7jSjR1Klop-YKaUHc9GsEofQqYruPhzSA-QgajZGPbE_');
  sbJwk.append('0ZaVDJHfyd7UUBUKunFMScbflYAAOYJqVIVwaYR5zWEEceUjNnTNo_CVSj');
  sbJwk.append('-VvXLO5VZfCUAVLgW4dpf1SrtZjSt34YLsRarSb127reG_DUwg9Ch-Kyvj');
  sbJwk.append('T1SkHgUWRVGcyly7uvVGRSDwsXypdrNinPA4jlhoNdizK2zF2CWQ",');
  sbJwk.append('"p":"9gY2w6I6S6L0juEKsbeDAwpd9WMfgqFoeA9vEyEUuk4kLwBKcoe1x4HG68');
  sbJwk.append('ik918hdDSE9vDQSccA3xXHOAFOPJ8R9EeIAbTi1VwBYnbTp87X-xcPWlEP');
  sbJwk.append('krdoUKW60tgs1aNd_Nnc9LEVVPMS390zbFxt8TN_biaBgelNgbC95sM",');
  sbJwk.append('"q":"uKlCKvKv_ZJMVcdIs5vVSU_6cPtYI1ljWytExV_skstvRSNi9r66jdd9-y');
  sbJwk.append('BhVfuG4shsp2j7rGnIio901RBeHo6TPKWVVykPu1iYhQXw1jIABfw-MVsN');
  sbJwk.append('-3bQ76WLdt2SDxsHs7q7zPyUyHXmps7ycZ5c72wGkUwNOjYelmkiNS0",');
  sbJwk.append('"dp":"w0kZbV63cVRvVX6yk3C8cMxo2qCM4Y8nsq1lmMSYhG4EcL6FWbX5h9yuv');
  sbJwk.append('ngs4iLEFk6eALoUS4vIWEwcL4txw9LsWH_zKI-hwoReoP77cOdSL4AVcra');
  sbJwk.append('Hawlkpyd2TWjE5evgbhWtOxnZee3cXJBkAi64Ik6jZxbvk-RR3pEhnCs",');
  sbJwk.append('"dq":"o_8V14SezckO6CNLKs_btPdFiO9_kC1DsuUTd2LAfIIVeMZ7jn1Gus_Ff');
  sbJwk.append('7B7IVx3p5KuBGOVF8L-qifLb6nQnLysgHDh132NDioZkhH7mI7hPG-PYE_');
  sbJwk.append('odApKdnqECHWw0J-F0JWnUd6D2B_1TvF9mXA2Qx-iGYn8OVV1Bsmp6qU",');
  sbJwk.append('"qi":"eNho5yRBEBxhGBtQRww9QirZsB66TrfFReG_CcteI1aCneT0ELGhYlRlC');
  sbJwk.append('tUkTRclIfuEPmNsNDPbLoLqqCVznFbvdB7x-Tl-m0l_eFTj2KiqwGqE9PZ');
  sbJwk.append('B9nNTwMVvH3VRRSLWACvPnSiwP8N5Usy-WRXS-V7TbpxIhvepTfE0NNo"');
  sbJwk.append('}');

  // Load this JWK into a Chilkat private key object.
  final rsaPrivKey = CkPrivateKey();
  try {
    rsaPrivKey.loadJwk(sbJwk.getAsString());
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The public key is used to encrypt (i.e. create the JWE), 
  // and the private key is used to decrypt.
  // The RSA public key is simply a subset of the private key.  The RSA public key
  // is composed of the "n" and "e" members shown above.  These are also known as the
  // modulus and exponent.
  // We can simply get the public key object from the private key object
  final rsaPubKey = CkPublicKey();
  rsaPrivKey.toPublicKey(rsaPubKey);

  // Create the JWE...
  final jwe = CkJwe();
  jwe.setProtectedHeader(jweProtHdr);
  jwe.setPublicKey(0, rsaPubKey);

  final String strJwe;
  try {
    strJwe = jwe.encrypt(plaintext, 'utf-8');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Show the JWE we just created:
  print(strJwe);

  // Note: The RSA PKCS1_V1_5 padding uses random value, and the results
  // will be different each time.  However, each result should be successfully
  // decrypting if using the correct RSA private key.

  // Let's decrypt the JWE that was just produced.
  // Do the following to decrypt a JWE:
  // 1) Load the JWE.
  // 2) Set the private key for decryption.
  // 3) Decrypt.
  final jwe2 = CkJwe();
  try {
    jwe2.loadJwe(strJwe);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Provide the RSA private key for decryption.
  // (The JWE was encrypted for a single recipient at index 0.)
  jwe2.setPrivateKey(0, rsaPrivKey);

  // Decrypt.
  String originalPlaintext;
  try {
    originalPlaintext = jwe2.decrypt(0, 'utf-8');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('original text: ');
  print(originalPlaintext);

  // ---------------------------------------------------------------------------------
  // It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.2.7
  // because it was produced using the same RSA key.

  final sbJwe = CkStringBuilder();
  sbJwe.append('eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.');
  sbJwe.append('UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm');
  sbJwe.append('1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc');
  sbJwe.append('HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF');
  sbJwe.append('NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8');
  sbJwe.append('rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv');
  sbJwe.append('-B3oWh2TbqmScqXMR4gp_A.');
  sbJwe.append('AxY8DCtDaGlsbGljb3RoZQ.');
  sbJwe.append('KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.');
  sbJwe.append('9hH0vgRfYgPnAHOd8stkvw');

  try {
    jwe2.loadJweSb(sbJwe);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Provide the RSA private key for decryption.
  jwe2.setPrivateKey(0, rsaPrivKey);

  // Decrypt.
  try {
    originalPlaintext = jwe2.decrypt(0, 'utf-8');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(originalPlaintext);
}