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Cryptojs aes password encryption helper for dart
import 'dart:convert';
import 'dart:math';
import 'dart:typed_data';
import 'package:crypto/crypto.dart';
import 'package:tuple/tuple.dart';
import 'package:encrypt/encrypt.dart' as encrypt;
String encryptAESCryptoJS(String plainText, String passphrase) {
try {
final salt = genRandomWithNonZero(8);
var keyndIV = deriveKeyAndIV(passphrase, salt);
final key = encrypt.Key(keyndIV.item1);
final iv = encrypt.IV(keyndIV.item2);
final encrypter = encrypt.Encrypter(
encrypt.AES(key, mode: encrypt.AESMode.cbc, padding: "PKCS7"));
final encrypted = encrypter.encrypt(plainText, iv: iv);
Uint8List encryptedBytesWithSalt = Uint8List.fromList(
createUint8ListFromString("Salted__") + salt + encrypted.bytes);
return base64.encode(encryptedBytesWithSalt);
} catch (error) {
throw error;
}
}
String decryptAESCryptoJS(String encrypted, String passphrase) {
try {
Uint8List encryptedBytesWithSalt = base64.decode(encrypted);
Uint8List encryptedBytes =
encryptedBytesWithSalt.sublist(16, encryptedBytesWithSalt.length);
final salt = encryptedBytesWithSalt.sublist(8, 16);
var keyndIV = deriveKeyAndIV(passphrase, salt);
final key = encrypt.Key(keyndIV.item1);
final iv = encrypt.IV(keyndIV.item2);
final encrypter = encrypt.Encrypter(
encrypt.AES(key, mode: encrypt.AESMode.cbc, padding: "PKCS7"));
final decrypted =
encrypter.decrypt64(base64.encode(encryptedBytes), iv: iv);
return decrypted;
} catch (error) {
throw error;
}
}
Tuple2<Uint8List, Uint8List> deriveKeyAndIV(String passphrase, Uint8List salt) {
var password = createUint8ListFromString(passphrase);
Uint8List concatenatedHashes = Uint8List(0);
Uint8List currentHash = Uint8List(0);
bool enoughBytesForKey = false;
Uint8List preHash = Uint8List(0);
while (!enoughBytesForKey) {
int preHashLength = currentHash.length + password.length + salt.length;
if (currentHash.length > 0)
preHash = Uint8List.fromList(
currentHash + password + salt);
else
preHash = Uint8List.fromList(
password + salt);
currentHash = md5.convert(preHash).bytes;
concatenatedHashes = Uint8List.fromList(concatenatedHashes + currentHash);
if (concatenatedHashes.length >= 48) enoughBytesForKey = true;
}
var keyBtyes = concatenatedHashes.sublist(0, 32);
var ivBtyes = concatenatedHashes.sublist(32, 48);
return new Tuple2(keyBtyes, ivBtyes);
}
Uint8List createUint8ListFromString(String s) {
var ret = new Uint8List(s.length);
for (var i = 0; i < s.length; i++) {
ret[i] = s.codeUnitAt(i);
}
return ret;
}
Uint8List genRandomWithNonZero(int seedLength) {
final random = Random.secure();
const int randomMax = 245;
final Uint8List uint8list = Uint8List(seedLength);
for (int i=0; i < seedLength; i++) {
uint8list[i] = random.nextInt(randomMax)+1;
}
return uint8list;
}
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