Example code for webcrypto.hmac.dart

hmac.dart

import 'package:webcrypto/webcrypto.dart';
  import 'dart:convert';
  
  Future<void> main() async {
    // Generate a new key using SHA-256 and an optional length parameter.
    final key = await HmacSecretKey.generateKey(Hash.sha256, length: 256);
    
    // Sign the message.
    final signature = await key.signBytes(utf8.encode('Hello World!'));
  
    // Verify the signature.
    final verified = await key.verifyBytes(signature, utf8.encode('Hello World!'));
    assert(verified == true, 'Signature should be valid');
  
    // Sign a stream of data.
    final signatureStream = await key.signStream(Stream.fromIterable([
      utf8.encode('Hello, '),
      utf8.encode('World!'),
    ]));
  
    // Verify the signature.
    final verifiedStream = await key.verifyStream(signatureStream, Stream.fromIterable([
      utf8.encode('Hello, '),
      utf8.encode('World!'),
    ]));
    assert(verifiedStream == true, 'Signature should be valid');
  
    // Export the key as raw bytes.
    final rawKey = await key.exportRawKey();
  
   // Export the key as a JSON Web Key.
   final jwk = await key.exportJsonWebKey();

    print('Signature: $signature');
    print('Signature verified: $verified');
    print('Signature Stream: $signatureStream');
    print('Signature Stream verified: $verifiedStream');
    print('Raw key: $rawKey');
    print('JSON Web Key: $jwk');
  }

log

Signature: [88, 74, 54, 182, 155, 248, 154, 227, 81, 159, 198, 185, 54, 137, 100, 88, 92, 209, 232, 134, 16, 11, 244, 22, 117, 77, 47, 124, 219, 94, 91, 149]
Signature verified: true
Signature Stream: [199, 161, 4, 221, 183, 159, 228, 12, 38, 131, 48, 86, 74, 199, 7, 233, 145, 16, 108, 181, 166, 8, 206, 8, 143, 97, 218, 151, 70, 57, 211, 194]
Signature Stream verified: true
Raw key: [102, 85, 5, 77, 3, 243, 191, 43, 174, 88, 169, 154, 216, 5, 245, 54, 113, 51, 166, 118, 215, 204, 220, 180, 140, 164, 95, 143, 212, 70, 210, 135]
JSON Web Key: {kty: oct, use: sig, alg: HS256, k: ZlUFTQPzvyuuWKma2AX1NnEzpnbXzNy0jKRfj9RG0oc}