149 lines
3.9 KiB
Dart
149 lines
3.9 KiB
Dart
// Copyright (c) 2020
|
|
// Author: Hugo Pointcheval
|
|
import 'dart:typed_data';
|
|
|
|
import 'package:native_crypto/src/native_crypto.dart';
|
|
import 'package:native_crypto/src/exceptions.dart';
|
|
|
|
/// Defines all available key sizes.
|
|
enum KeySize { bits128, bits192, bits256 }
|
|
|
|
/// Defines all available ciphers.
|
|
enum Cipher { AES }
|
|
|
|
/// Key Helper
|
|
///
|
|
/// You can generate Secret keys of different sizes.
|
|
class KeyGenerator {
|
|
/// Generate a secret key.
|
|
///
|
|
/// You can specify a `keySize`. Default is 256 bits.
|
|
Future<Uint8List> secretKey({KeySize keySize}) async {
|
|
int size;
|
|
switch (keySize) {
|
|
case KeySize.bits128:
|
|
size = 128;
|
|
break;
|
|
case KeySize.bits192:
|
|
size = 192;
|
|
break;
|
|
case KeySize.bits256:
|
|
size = 256;
|
|
break;
|
|
default:
|
|
// Default size = 256 bits
|
|
size = 256;
|
|
break;
|
|
}
|
|
return await NativeCrypto().symKeygen(size);
|
|
}
|
|
}
|
|
|
|
/// AES Helper
|
|
///
|
|
/// You can encrypt and decrypt data.
|
|
class AES {
|
|
Uint8List _key;
|
|
|
|
bool _isInitialized = false;
|
|
|
|
KeySize _keySize;
|
|
|
|
/// You can pass a key in constructor.
|
|
AES({Uint8List key}) {
|
|
this._key = key;
|
|
try {
|
|
this._isInitialized = _testKey();
|
|
} on KeyException {
|
|
this._isInitialized = false;
|
|
throw KeyException('Invalid key length: ${this.key.length} Bytes');
|
|
}
|
|
}
|
|
|
|
/// This key is used for encryption and decryption.
|
|
Uint8List get key => this._key;
|
|
|
|
/// Check if the AES object is intialized with a valid key before perform any operation.
|
|
bool get isInitialized => this._isInitialized;
|
|
|
|
/// Defines the size of the generated or passed key.
|
|
KeySize get keySize => this._keySize;
|
|
|
|
/// [Private]
|
|
/// Tests if the key is valid.
|
|
///
|
|
/// The key must be 128, 192 or 256 bits long.
|
|
bool _testKey() {
|
|
if (this.key != null) {
|
|
switch (this.key.length) {
|
|
case 16:
|
|
this._keySize = KeySize.bits128;
|
|
break;
|
|
case 24:
|
|
this._keySize = KeySize.bits192;
|
|
break;
|
|
case 32:
|
|
this._keySize = KeySize.bits256;
|
|
break;
|
|
default:
|
|
throw KeyException('Invalid key length: ${this.key.length} Bytes');
|
|
}
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/// Generate an AES key.
|
|
///
|
|
/// You have to specify a `keySize`.
|
|
/// Return `null` if the key is already set.
|
|
init(KeySize keySize) async {
|
|
if (this.key != null) return null;
|
|
|
|
this._keySize = keySize;
|
|
this._key = await KeyGenerator().secretKey(keySize: keySize);
|
|
|
|
try {
|
|
this._isInitialized = _testKey();
|
|
} on KeyException {
|
|
this._isInitialized = false;
|
|
throw KeyException('Invalid key length: ${this.key.length} Bytes');
|
|
}
|
|
}
|
|
|
|
/// Encrypts data.
|
|
///
|
|
/// Takes `Uint8List` data as parameter.
|
|
/// And returns an `Uint8List` **list**.
|
|
///
|
|
/// You can pass a different key.
|
|
///
|
|
/// The first member of this list is the `cipher data`,
|
|
/// and the second member is the `IV`.
|
|
Future<List<Uint8List>> encrypt(Uint8List data, {Uint8List key}) async {
|
|
if (!this._isInitialized && key == null)
|
|
throw EncryptionException(
|
|
'Instance not initialized. You can pass a key directly in encrypt method.');
|
|
|
|
List<Uint8List> encryptedPayload =
|
|
await NativeCrypto().symEncrypt(data, key ?? this.key);
|
|
return encryptedPayload;
|
|
}
|
|
|
|
/// Decrypts data.
|
|
///
|
|
/// Takes `Uint8List` **list** as parameter.
|
|
/// And returns plain text data as `Uint8List`.
|
|
///
|
|
/// You can pass a different key.
|
|
Future<Uint8List> decrypt(List<Uint8List> encryptedPayload, {Uint8List key}) async {
|
|
if (!this._isInitialized && key == null)
|
|
throw DecryptionException(
|
|
'Instance not initialized. You can pass a key directly in encrypt method.');
|
|
Uint8List decryptedPayload =
|
|
await NativeCrypto().symDecrypt(encryptedPayload, key ?? this.key);
|
|
return decryptedPayload;
|
|
}
|
|
}
|