113 lines
2.9 KiB
Dart
113 lines
2.9 KiB
Dart
// Copyright (c) 2020
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// Author: Hugo Pointcheval
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import 'dart:typed_data';
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import 'package:native_crypto/native_crypto.dart';
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import 'package:native_crypto/src/exceptions.dart';
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enum KeySize { bits128, bits192, bits256 }
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enum Cipher { AES }
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/// AES Helper
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///
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/// You can generate AES keys, encrypt and decrypt data.
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class AES {
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Uint8List key;
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bool isInitialized = false;
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KeySize keySize;
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/// You can pass a key in constructor.
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AES({this.key}) {
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try {
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bool isValidKey = _testKey();
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this.isInitialized = isValidKey;
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} on KeyException {
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this.isInitialized = false;
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throw KeyException('Invalid key length.');
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}
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}
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/// Tests if the key is valid.
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///
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/// The key must be 128, 192 or 256 bits long.
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bool _testKey() {
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if (this.key != null) {
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switch (this.key.length) {
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case 16:
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this.keySize = KeySize.bits128;
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break;
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case 24:
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this.keySize = KeySize.bits192;
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break;
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case 32:
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this.keySize = KeySize.bits256;
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break;
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default:
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throw KeyException('Invalid key length.');
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}
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return true;
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} else {
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return false;
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}
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}
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/// Generate an AES key.
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init(KeySize keySize) async {
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if (this.key != null) return null;
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if (keySize != KeySize.bits256)
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throw NotImplementedException('This key size is not implemented yet.');
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this.key = await NativeCrypto().symKeygen();
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try {
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bool isValidKey = _testKey();
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this.isInitialized = isValidKey;
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} on KeyException {
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this.isInitialized = false;
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throw KeyException('Invalid key length.');
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}
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}
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/// Encrypt data
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///
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/// Returns an `Encrypted` object.
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Future<Encrypted> encrypt(Uint8List data) async {
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if (!this.isInitialized) throw EncryptionException('Instance not initialized.');
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List<Uint8List> encryptedPayload =
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await NativeCrypto().symEncrypt(data, this.key);
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Encrypted encrypted = Encrypted.fromList(Cipher.AES, encryptedPayload);
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return encrypted;
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}
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Future<Uint8List> decrypt(Encrypted encrypted) async {
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if (!this.isInitialized) throw DecryptionException('Instance not initialized.');
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Uint8List decryptedPayload =
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await NativeCrypto().symDecrypt(encrypted.toList(), this.key);
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return decryptedPayload;
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}
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}
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/// Contains data of an encrypted payload.
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/// More practical than a list.
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class Encrypted {
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Cipher cipher;
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Uint8List cipherText;
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Uint8List iv;
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Uint8List mac;
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Encrypted();
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Encrypted.fromList(this.cipher, List<Uint8List> encryptedPayload) {
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this.mac = encryptedPayload[0].sublist(0, 32);
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this.cipherText = encryptedPayload[0].sublist(32, encryptedPayload[0].length);
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this.iv = encryptedPayload[1];
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}
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List<Uint8List> toList() {
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List<Uint8List> encryptedPayload = [Uint8List.fromList(this.mac + this.cipherText), this.iv];
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return encryptedPayload;
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}
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}
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