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Dart

Load and Validate a JWS from a String

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.LoadJws, which loads a JWS from its compact serialization string. The example then supplies the MAC key and validates the signature.

Background. Validate returns 1 when the signature or MAC is cryptographically valid, 0 when it is not, or a negative value on error. The key for the signer index must be provided before validating.

Chilkat Dart Downloads

Dart
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 HMAC key for signer 0, then validate the signature.  Validate returns 1 when the
  // signature is cryptographically valid, 0 when it is not, or a negative value on error.
  final base64Key = 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  try {
    jws.setMacKey(0, base64Key, 'base64');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final v = jws.validate(0);
  if (v < 0) {
    print(jws.lastErrorText);
    return;
  }

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

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