Hmac class abstract

HMAC, a widely used MacAlgorithm.

DartHmac is the pure Dart implementation of the HMAC algorithm. It's used when no faster implementation is available.

In browsers, "package:cryptography" will automatically attempt to use Web Crypto API, which has very good HMAC performance.

Flutter developers should add cryptography_flutter, as a dependency for the best possible HMAC performance.

Things to know

• You must choose some HashAlgorithm. We have shorthands constructors such as Hmac.sha256, but the hash algorithm can be anything.
• HMAC does not support nonces. Our implementation ignores any nonce.
• HMAC does not support AAD (Associated Authenticated Data). Our implementation throws ArgumentError if you try to give some.

Constructors

• Hmac.blake2b for HMAC-BLAKE2B.
• Hmac.blake2s for HMAC-BLAKE2S.
• Hmac.sha1 for HMAC-SHA1.
• Hmac.sha224 for HMAC-SHA224.
• Hmac.sha256 for HMAC-SHA256.
• Hmac.sha384 for HMAC-SHA384.
• Hmac.sha512 for HMAC-SHA512.
• For other combinations, give hash algorithm in the constructor (example: Hmac(Blake2s())).

Example

import 'package:cryptography/cryptography.dart';

void main() async {
  final message = [1,2,3];
  final secretKey = SecretKey([4,5,6]);

  // In our example, we calculate HMAC-SHA256
  final hmac = Hmac.sha256();
  final mac = await hmac.calculateMac(
    message,
    secretKey: secretKey,
  );
}

Example: synchronous usage

DartHmac, a pure Dart implementation of HMAC, can be used when you absolutely need do computations synchronously:

import 'package:cryptography/cryptography.dart';
import 'package:cryptography/dart.dart';

void main() {
  final algorithm = DartHmac.sha256();
  final mac = algorithm.calculateMacSync(
    bytes,
    secretKey: secretKey,
  );
}

Inheritance

• Object
• MacAlgorithm
• Hmac

Implementers

• DartHmac

Constructors

Hmac(HashAlgorithm hashAlgorithm)

Constructs HMAC with any hash algorithm.

factory

Hmac.blake2b()

HMAC-BLAKE2B.

factory

Hmac.blake2s()

HMAC-BLAKE2S.

factory

Hmac.constructor()

Constructor for classes that extend this class.

const

Hmac.sha1()

HMAC with Sha1.

factory

Hmac.sha224()

HMAC with Sha224.

factory

Hmac.sha256()

HMAC with Sha256.

factory

Hmac.sha384()

HMAC with Sha384.

factory

Hmac.sha512()

HMAC with Sha512.

factory

Properties

hashAlgorithm → HashAlgorithm

Hash algorithm used by the HMAC.

no setter

hashCode → int

The hash code for this object.

no setter, override

keyStreamUsed → int

Number of bytes in key stream used to initialize the MAC algorithm.

no setter, inherited

macLength → int

Number of bytes in the message authentication code.

no setter, override

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

supportsAad → bool

Whether the algorithm supports Associated Authenticated Data (AAD).

no setter, inherited

supportsKeyStreamIndex → bool

Whether the algorithm supports key stream index.

no setter, inherited

Methods

calculateMac(List<int> bytes, {required SecretKey secretKey, List<int> nonce = const <int>[], List<int> aad = const <int>[]}) → Future<Mac>

Calculates message authentication code.

inherited

checkParameters({int? length, required SecretKey secretKey, required int nonceLength, required int aadLength, required int keyStreamIndex}) → void

Checks parameters and throws ArgumentError if they are invalid.

inherited

newMacSink({required SecretKey secretKey, List<int> nonce = const <int>[], List<int> aad = const <int>[]}) → Future<MacSink>

Constructs a sink for calculating a Mac.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

override

toSync() → DartHmac

Returns a synchronous implementation of this algorithm.

override

Operators

operator ==(Object other) → bool

The equality operator.

override