hmac function
Implementation
Future<Uint8List> hmac(dynamic key, String message) async {
Uint8List keyBuffer;
if (key is String) {
keyBuffer = Uint8List.fromList(utf8.encode(key));
} else if (key is Uint8List) {
keyBuffer = key;
} else {
throw ArgumentError('Invalid key type');
}
Uint8List messageBuffer = Uint8List.fromList(utf8.encode(message));
Hmac hmac = Hmac(sha256, keyBuffer);
Digest digest = hmac.convert(messageBuffer);
return Uint8List.fromList(digest.bytes);
}