Validate a JWS Signature

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.Validate, which validates exactly one signature, identified by a zero-based index, using the key configured at that same index.

import 'package:chilkat/chilkat.dart';

void main() {
  final jws = CkJws();

  // Load the JWS compact serialization.
  final jwsCompact = 'eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>';
  try {
    jws.loadJws(jwsCompact);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Provide the key for signature 0 (here an HMAC key).
  final base64Key = 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  try {
    jws.setMacKey(0, base64Key, 'base64');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Validate the signature identified by the zero-based index, using the key configured at that index.
  // Validate returns 1 when the signature or MAC is cryptographically valid, 0 when it is not, or a
  // negative value on error.
  final v = jws.validate(0);
  if (v < 0) {
    print(jws.lastErrorText);
    return;
  }

  if (v != 1) {
    print(jws.lastErrorText);
    print('The signature is not valid.');
    return;
  }

  print('The signature is valid.');
}