Dart

Compute JWK Thumbprint for RSA and EC Public Keys

See more ECC Examples

Demonstrates how to compute a JSON Web Key thumbprint for a public key (RSA or ECC).

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

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final pubKey = CkPublicKey();

  // A public key can be loaded from any format (binary DER, PEM, etc.)
  // This example will load the public keys from JWK format, 
  // and will then compute the JWK thumbprint.

  // First do it for an RSA public key...

  final sb = CkStringBuilder();
  sb.append('{');
  sb.append('"kty": "RSA",');
  sb.append('"n": "0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAt');
  sb.append('VT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMstn6');
  sb.append('4tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FD');
  sb.append('W2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n9');
  sb.append('1CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINH');
  sb.append('aQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",');
  sb.append('"e": "AQAB",');
  sb.append('"alg": "RS256",');
  sb.append('"kid": "2011-04-29"');
  sb.append('}');

  // The JWK format is automatically detected..
  try {
    pubKey.loadFromString(sb.getAsString());
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Get the JWK thumbprint (using SHA256)
  print('JWK thumbprint: ${pubKey.getJwkThumbprint('SHA256')}');

  // Output:
  // JWK thumbprint: NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs

  // --------------------------------------------------------------
  // Now let's do an EC public key:
  sb.clear();
  sb.append('{ ');
  sb.append('  "kty": "EC",');
  sb.append('  "crv": "P-256",');
  sb.append('  "x": "tDeeYABgKEAbWicYPCEEI8sP4SRIhHKcHDW7VqrB4LA",');
  sb.append('  "y": "J08HOoIZ0rX2Me3bNFZUltfxIk1Hrc8FsLu8VaSxsMI"');
  sb.append('}');

  try {
    pubKey.loadFromString(sb.getAsString());
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Get the JWK thumbprint (using SHA256)
  print('JWK thumbprint: ${pubKey.getJwkThumbprint('SHA256')}');

  // Output:
  // JWK thumbprint: 8fm8079s3nu4FLV_7dVJoJ69A8XCXn7Za2mtaWCnxR4
}