Chacha20 class abstract

ChaCha20 (RFC 7539) StreamingCipher.

Unless you really know what you are doing, you should use Chacha20.poly1305Aead constructor, which constructs the popular AEAD version of the cipher.

Implementations

By default, DartChacha20 will be used. It is a pure Dart implementation.

If you use Flutter, you can enable cryptography_flutter. It can improve performance in many cases.

Things to know

secretKeyLength is 32 bytes.
nonceLength is 12 bytes.
If you use Chacha20.poly1305Aead (like you should), MAC algorithm is not needed. Otherwise must specify some MacAlgorithm.

Example

import 'package:cryptography/cryptography.dart';

Future<void> main() async {
  final message = <int>[1,2,3];

  final algorithm = Chacha20(macAlgorithm: Hmac.sha256());
  final secretKey = await algorithm.newSecretKey();

  // Encrypt
  final secretBox = await algorithm.encrypt(
    message,
    secretKey: secretKey,
  );
  print('Nonce: ${secretBox.nonce}')
  print('Ciphertext: ${secretBox.cipherText}')
  print('MAC: ${secretBox.mac.bytes}')

  // Decrypt
  final clearText = await algorithm.decrypt(
    secretBox,
    secretKey: secretKey,
  );
  print('Cleartext: $clearText');
}

Inheritance

Implementers

DartChacha20

Constructors

Chacha20({required MacAlgorithm macAlgorithm}): Constructs a ChaCha20 with any MAC.
factory
Chacha20.constructor({Random? random}): Constructor for classes that extend this class.
const
Chacha20.poly1305Aead(): Constructs ChaCha20-Poly1305-AEAD cipher ((RFC 7539, also known as AEAD_CHACHA20_POLY1305), which is a popular authenticating cipher based on ChaCha20.
factory

Properties

hashCode → int: The hash code for this object.
no setteroverride
macAlgorithm → MacAlgorithm: Message authentication code (MacAlgorithm) used by the cipher.
no setterinherited
nonceLength → int: Number of bytes in the nonce ("Initialization Vector", "IV", "salt").
no setteroverride
random → Random?: Random number generator used by newSecretKey for generating secret keys.
finalinherited
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
secretKeyLength → int: Number of bytes in the SecretKey.
no setteroverride

Methods

checkParameters({int? length, required SecretKey secretKey, required int nonceLength, int aadLength = 0, int keyStreamIndex = 0}) → void: Checks parameters for encrypt / decrypt and throws ArgumentError if any is invalid.
inherited
cipherTextLength(int clearTextLength) → int: Calculates the length of the ciphertext given a clear text length.
inherited
decrypt(SecretBox secretBox, {required SecretKey secretKey, List<int> aad = const <int>[], int keyStreamIndex = 0, Uint8List? possibleBuffer}) → Future<List<int>>: Decrypts a ciphertext.
inherited
decryptStream(Stream<List<int>> stream, {required SecretKey secretKey, required List<int> nonce, required FutureOr<Mac> mac, List<int> aad = const [], bool allowUseSameBytes = false}) → Stream<List<int>>: Decrypts a Stream of bytes.
inherited
decryptString(SecretBox secretBox, {required SecretKey secretKey}) → Future<String>: Calls decrypt and then converts the bytes to a string by using utf8 codec.
inherited
encrypt(List<int> clearText, {required SecretKey secretKey, List<int>? nonce, List<int> aad = const <int>[], int keyStreamIndex = 0, Uint8List? possibleBuffer}) → Future<SecretBox>: Encrypts a cleartext.
inherited
encryptStream(Stream<List<int>> stream, {required SecretKey secretKey, required List<int> nonce, required void onMac(Mac mac), List<int> aad = const [], bool allowUseSameBytes = false}) → Stream<List<int>>: Encrypts a Stream of bytes.
inherited
encryptString(String clearText, {required SecretKey secretKey}) → Future<SecretBox>: Converts a string to bytes using utf8 codec and then calls encrypt.
inherited
newCipherWand() → Future<CipherWand>: Constructs a CipherWand that uses this implementation and a new random secret key (that can't be extracted).
inherited
newCipherWandFromSecretKey(SecretKey secretKey, {bool allowEncrypt = true, bool allowDecrypt = true}) → Future<CipherWand>: Constructs a CipherWand that uses this implementation and the given SecretKey.
inherited
newNonce() → List<int>: Generates a new nonce.
inherited
newSecretKey() → Future<SecretKey>: Generates a new SecretKey.
inherited
newSecretKeyFromBytes(List<int> bytes) → Future<SecretKey>: Constructs a new SecretKey from the bytes.
inherited
newState() → CipherState: 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() → DartChacha20: Returns a synchronous, pure Dart implementation of this cipher.
override

Operators

operator ==(Object other) → bool: The equality operator.
override