Dart Requires Chilkat v11.0.0+

JWS Using RSASSA-PSS using SHA-256 and MGF1 with SHA-256

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using RSASSA-PSS using SHA-256 and MGF1 with SHA-256.

Chilkat supports all of the following JWS algorithms:

   +--------------+-------------------------------+--------------------+
   | "alg" Param  | Digital Signature or MAC      | Implementation     |
   | Value        | Algorithm                     | Requirements       |
   +--------------+-------------------------------+--------------------+
   | HS256        | HMAC using SHA-256            | Required           |
   | HS384        | HMAC using SHA-384            | Optional           |
   | HS512        | HMAC using SHA-512            | Optional           |
   | RS256        | RSASSA-PKCS1-v1_5 using       | Recommended        |
   |              | SHA-256                       |                    |
   | RS384        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-384                       |                    |
   | RS512        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-512                       |                    |
   | ES256        | ECDSA using P-256 and SHA-256 | Recommended+       |
   | ES384        | ECDSA using P-384 and SHA-384 | Optional           |
   | ES512        | ECDSA using P-521 and SHA-512 | Optional           |
   | PS256        | RSASSA-PSS using SHA-256 and  | Optional           |
   |              | MGF1 with SHA-256             |                    |
   | PS384        | RSASSA-PSS using SHA-384 and  | Optional           |
   |              | MGF1 with SHA-384             |                    |
   | PS512        | RSASSA-PSS using SHA-512 and  | Optional           |
   |              | MGF1 with SHA-512             |                    |
   +--------------+-------------------------------+--------------------+

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.

  // Use the following RSA key loaded from JWK format.
  final sbJwk = CkStringBuilder();
  sbJwk.append('{"kty":"RSA",');
  sbJwk.append('"n":"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx');
  sbJwk.append('HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs');
  sbJwk.append('D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH');
  sbJwk.append('SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV');
  sbJwk.append('MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8');
  sbJwk.append('NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ",');
  sbJwk.append('"e":"AQAB",');
  sbJwk.append('"d":"Eq5xpGnNCivDflJsRQBXHx1hdR1k6Ulwe2JZD50LpXyWPEAeP88vLNO97I');
  sbJwk.append('jlA7_GQ5sLKMgvfTeXZx9SE-7YwVol2NXOoAJe46sui395IW_GO-pWJ1O0');
  sbJwk.append('BkTGoVEn2bKVRUCgu-GjBVaYLU6f3l9kJfFNS3E0QbVdxzubSu3Mkqzjkn');
  sbJwk.append('439X0M_V51gfpRLI9JYanrC4D4qAdGcopV_0ZHHzQlBjudU2QvXt4ehNYT');
  sbJwk.append('CBr6XCLQUShb1juUO1ZdiYoFaFQT5Tw8bGUl_x_jTj3ccPDVZFD9pIuhLh');
  sbJwk.append('BOneufuBiB4cS98l2SR_RQyGWSeWjnczT0QU91p1DhOVRuOopznQ",');
  sbJwk.append('"p":"4BzEEOtIpmVdVEZNCqS7baC4crd0pqnRH_5IB3jw3bcxGn6QLvnEtfdUdi');
  sbJwk.append('YrqBdss1l58BQ3KhooKeQTa9AB0Hw_Py5PJdTJNPY8cQn7ouZ2KKDcmnPG');
  sbJwk.append('BY5t7yLc1QlQ5xHdwW1VhvKn-nXqhJTBgIPgtldC-KDV5z-y2XDwGUc",');
  sbJwk.append('"q":"uQPEfgmVtjL0Uyyx88GZFF1fOunH3-7cepKmtH4pxhtCoHqpWmT8YAmZxa');
  sbJwk.append('ewHgHAjLYsp1ZSe7zFYHj7C6ul7TjeLQeZD_YwD66t62wDmpe_HlB-TnBA');
  sbJwk.append('-njbglfIsRLtXlnDzQkv5dTltRJ11BKBBypeeF6689rjcJIDEz9RWdc",');
  sbJwk.append('"dp":"BwKfV3Akq5_MFZDFZCnW-wzl-CCo83WoZvnLQwCTeDv8uzluRSnm71I3Q');
  sbJwk.append('CLdhrqE2e9YkxvuxdBfpT_PI7Yz-FOKnu1R6HsJeDCjn12Sk3vmAktV2zb');
  sbJwk.append('34MCdy7cpdTh_YVr7tss2u6vneTwrA86rZtu5Mbr1C1XsmvkxHQAdYo0",');
  sbJwk.append('"dq":"h_96-mK1R_7glhsum81dZxjTnYynPbZpHziZjeeHcXYsXaaMwkOlODsWa');
  sbJwk.append('7I9xXDoRwbKgB719rrmI2oKr6N3Do9U0ajaHF-NKJnwgjMd2w9cjz3_-ky');
  sbJwk.append('NlxAr2v4IKhGNpmM5iIgOS1VZnOZ68m6_pbLBSp3nssTdlqvd0tIiTHU",');
  sbJwk.append('"qi":"IYd7DHOhrWvxkwPQsRM2tOgrjbcrfvtQJipd-DlcxyVuuM9sQLdgjVk2o');
  sbJwk.append('y26F0EmpScGLq2MowX7fhd_QJQ3ydy5cY7YIBi87w93IKLEdfnbJtoOPLU');
  sbJwk.append('W0ITrJReOgo1cq9SbsxYawBgfp_gh6A5603k2-ZQwVK0JKSHuLFkuQ3U"');
  sbJwk.append('}');

  final rsaKey = CkPrivateKey();
  // Note: This example loads the RSA key from JWK format.  Any format can be loaded
  // into the private key object. (See the online reference documentation..)
  try {
    rsaKey.loadJwk(sbJwk.getAsString());
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Create the JWS Protected Header
  final jwsProtHdr = CkJsonObject();
  jwsProtHdr.appendString('alg', 'PS256');

  final jws = CkJws();

  // Set the protected header:
  var signatureIndex = 0;
  jws.setProtectedHeader(signatureIndex, jwsProtHdr);

  // Set the RSA key:
  jws.setPrivateKey(signatureIndex, rsaKey);

  // Set the payload.
  final bIncludeBom = false;
  final payloadStr = 'In our village, folks say God crumbles up the old moon into stars.';
  jws.setPayload(payloadStr, 'utf-8', bIncludeBom);

  // Create the JWS
  // By default, the compact serialization is used.
  final String jwsCompact;
  try {
    jwsCompact = jws.createJws();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('JWS: $jwsCompact');

  // Note: RSA PSS padding uses random values, so the output will be different each time a signature is produced.
  // sample output:
  // JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

  // Now load the JWS, validate, and recover the original text.
  final jws2 = CkJws();

  // Load the JWS.
  jws2.loadJws(jwsCompact);

  final rsaPubKey = CkPublicKey();
  rsaKey.toPublicKey(rsaPubKey);

  // Set the RSA public key used for validation.
  signatureIndex = 0;
  jws2.setPublicKey(signatureIndex, rsaPubKey);

  // Validate the 1st (and only) signature at index 0..
  final v = jws2.validate(signatureIndex);
  if (v < 0) {
    // Perhaps Chilkat was not unlocked or the trial expired..
    print('Method call failed for some other reason.');
    print(jws2.lastErrorText);
    return;
  }

  if (v == 0) {
    print('Invalid signature.  The RSA key was incorrect, the JWS was invalid, or both.');
    return;
  }

  // If we get here, the signature was validated..
  print('Signature validated.');

  // Recover the original content:
  print(jws2.getPayload('utf-8'));

  // Examine the protected header:
  final joseHeader = CkJsonObject();
  jws2.getProtectedH(signatureIndex, joseHeader);
  joseHeader.emitCompact = false;

  print('Protected (JOSE) header:');
  print(joseHeader.emit());

  // Output:

  // 	Signature validated.
  // 	In our village, folks say God crumbles up the old moon into stars.
  // 	Protected (JOSE) header:
  // 	{ 
  // 	  "alg": "PS256"
  // 	}
}