Decryption in Java for String Encrypted in C# using AES - java

I am trying to write a code equivalent of following c# code to decrypt a string in Java.
public string Decrypt(string cipherText)
{
if (!IsBase64String(cipherText))
throw new Exception("The cipherText input parameter is not base64 encoded");
string text;
var key = new Rfc2898DeriveBytes(EncryptionKey, SALT);
var aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
aesAlg.IV = key.GetBytes(aesAlg.BlockSize / 8);
var decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV); var cipher = Convert.FromBase64String(cipherText);
using (var msDecrypt = new MemoryStream(cipher))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
{
// Internal
text = srDecrypt.ReadToEnd();
}
}
}
return text;
}
Here is what I tried:
final String password = "password";
byte[] salt = []; //salt provided here
String string = "something";
System.out.println(string.length());
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 1000, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKeySpec secret = new SecretKeySpec(tmp.getEncoded(), "AES");
byte[] data = Base64.getDecoder().decode(string);
System.out.println(data.length);
// skip first 4 bytes (the length of IV) and get IV byte array
byte[] iv = Arrays.copyOfRange(data, 16, 32);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
// skip IV length (4 bytes) and IV (16 bytes)
cipher.update(data, 32, data.length - 32);
String plaintext = new String(cipher.doFinal(), "UTF-8");
System.out.println(plaintext);
Getting the following Exception:
javax.crypto.BadPaddingException: Given final block not properly padded. Such issues can arise if a bad key is used during decryption.
Not sure where I went wrong

Related

AES/CBC/PKCS5Padding nodejs encryption

I am trying to convert my java code to NodeJs code. It's a little more complicate because the customised format included the password and salt.
In main method there is one example.
Here is my java code:
public class App {
private static final int DYN_SALT_LENGTH = 10;
private static final int ITERATION_COUNT = 65556;
private static final int KEY_LENGTH = 256;
private static final String SECRET_KEY_ALGORITHM = "AES";
private static final String CIPHER_TRANSFORMER = "AES/CBC/PKCS5Padding";
private static Base64 base64Instance = new Base64();
public static String decrypt(String data, String password, String salt) {
try {
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt.getBytes(StandardCharsets.UTF_8),
ITERATION_COUNT,
KEY_LENGTH);
SecretKey secretKey = factory.generateSecret(spec);
ByteBuffer buffer = ByteBuffer.wrap(base64Instance.decode(data));
buffer.position(DYN_SALT_LENGTH);
Cipher cipher = Cipher.getInstance(CIPHER_TRANSFORMER);
// Read the IV
byte[] ivBytes = new byte[cipher.getBlockSize()];
buffer.get(ivBytes, 0, ivBytes.length);
// Read encrypted text.
byte[] encryptedTextBytes = new byte[buffer.capacity() - DYN_SALT_LENGTH - ivBytes.length];
buffer.get(encryptedTextBytes);
// Initialize Cipher.
SecretKeySpec secret = new SecretKeySpec(secretKey.getEncoded(), SECRET_KEY_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(ivBytes));
String result = new String(cipher.doFinal(encryptedTextBytes), StandardCharsets.UTF_8);
return result;
} catch (Exception e) {
throw new RuntimeException("Failed to decrypt data", e);
}
}
public static String encrypt(String data, String password, String salt) {
// Create new salt for every new encryption request.
byte[] saltBytes = new byte[DYN_SALT_LENGTH];
new SecureRandom().nextBytes(saltBytes);
try {
// Create secret key spec.
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt.getBytes(StandardCharsets.UTF_8),
ITERATION_COUNT,
KEY_LENGTH);
SecretKey secretKey = factory.generateSecret(spec);
SecretKeySpec secret = new SecretKeySpec(secretKey.getEncoded(), SECRET_KEY_ALGORITHM);
byte[] ivBytes;
byte[] encryptedTextBytes;
// Initialize cipher
Cipher cipher = Cipher.getInstance(CIPHER_TRANSFORMER);
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
// Create initialization vector IV
ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
// Encrypt the text.
encryptedTextBytes = cipher.doFinal(data.getBytes(StandardCharsets.UTF_8));
// Response will be in the form of <salt><IV><encryptedText>
ByteBuffer byteBuffer = ByteBuffer.allocate(saltBytes.length + ivBytes.length + encryptedTextBytes.length);
byteBuffer.put(saltBytes);
byteBuffer.put(ivBytes);
byteBuffer.put(encryptedTextBytes);
return base64Instance.encodeToString(byteBuffer.array());
} catch (Exception e) {
throw new RuntimeException("Failed to encrypt data", e);
}
}
public static void main(String[] args) {
String password = "password";
String salt = "salt";
String data = "hello world";
String resultEncrypted = encrypt(data, password, salt);
System.out.println(resultEncrypted);
String resultDecrypted = decrypt(resultEncrypted, password, salt);
System.out.println(resultDecrypted);
}
}
I'm trying with JS code like below but without clue about what i'm doing wrong:
function getAlgorithm(keyBase64) {
var key = Buffer.from(keyBase64, "base64");
switch (key.length) {
case 16:
return "aes-128-cbc";
case 32:
return "aes-256-cbc";
}
throw new Error("Invalid key length: " + key.length);
}
function decrypt(messagebase64, keyBase64, ivBase64) {
const key = Buffer.from(keyBase64, "base64");
const iv = Buffer.from(ivBase64, "base64");
const decipher = crypto.createDecipheriv(
getAlgorithm(keyBase64),
key,
iv.slice(0, 16)
);
let decrypted = decipher.update(messagebase64, "base64", "utf8");
decrypted += decipher.final("utf8");
return decrypted;
}
const base64Encrypted =
"2vSIh0J64zhrQuayUV+UIyPTpmSaN4gAv7B3CVC/a68eBfeU0bMwRm2I";
const key = crypto.scryptSync("password", "salt", 16);
const encrypted = Buffer.from(base64Encrypted, "base64");
const encryptedWOSalt = Buffer.from(base64Encrypted, "base64").slice(10);
const iv = encrypted.slice(10, 10 + 17);
const result = decrypt(
encryptedWOSalt.toString("base64"),
key,
iv.toString("base64")
);
console.log(result);
It's throwing an error:
Error: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt
Thanks
Since you only posted a NodeJS decryption code, I focus on decryption. The encryption is to be implemented analogously. If you have problems with this, please post a new question with the corresponding encryption code.
There are several bugs in the NodeJS code:
Wrong key derivation (in the NodeJS code scrypt is used, while in the Java code PBKDF2/HMAC-SHA1 is applied).
Incorrect/missing separation of salt, IV and ciphertext
Encoding bugs and unnecessary encoding/decoding cycles
The following NodeJS code works:
var crypto = require('crypto')
function getAlgorithm(key) {
switch (key.length) {
case 16:
return "aes-128-cbc";
case 32:
return "aes-256-cbc";
}
throw new Error("Invalid key length: " + key.length);
}
function decrypt(message, key, iv) {
const decipher = crypto.createDecipheriv(
getAlgorithm(key),
key,
iv
);
let decrypted = Buffer.concat([decipher.update(message), decipher.final()]);
return decrypted.toString("utf8");
}
const DYN_SALT_LENGTH = 10;
const IV_LENGTH = 16;
const ITERATION_COUNT = 65556;
const KEY_LENGTH = 256;
const base64Encrypted = "ossqoyCaaQINWUkTsHNGRe5Isd5s7c7U8KcLua78Ehm9jAxQNOd2tyjj";
// Separate salt, IV and ciphertext
const encrypted = Buffer.from(base64Encrypted, "base64");
const salt = encrypted.slice(0, DYN_SALT_LENGTH);
const iv = encrypted.slice(DYN_SALT_LENGTH, DYN_SALT_LENGTH + IV_LENGTH);
const ciphertext = encrypted.slice(DYN_SALT_LENGTH + IV_LENGTH);
// Derive key voa PBKDF2/HMAC-SHA1
const key = crypto.pbkdf2Sync("password", "salt", ITERATION_COUNT, KEY_LENGTH/8, "sha1");
// Decrypt
const result = decrypt(
ciphertext,
key,
iv
);
console.log(result); // hello world
Note that the current Java code (and therefore also the NodeJS code) does not use the random salt for key derivation, but a static salt, possibly for testing purposes. In the final solution, the random salt is to be used for security reasons.

Encryption in Flutter and Decryption in java (AES-256)

I am trying to implement encryption in Flutter, I'm using java as a backend and dart for the mobile application. I have taken code from this Encryption in Java and Decryption in Flutter (AES-256)
But it only supplies decryption in Flutter, and I want to implement encryption in Flutter so the Java code can decrypt it.
Can you help me by providing the code for encryption in Flutter?
This is the java code for encryption and decryption.
public class EncryptionService {
public String encrypt(String item) throws Exception {
byte[] ivBytes;
String password = "Hello";
/* you can give whatever you want for password. This is for testing purpose */
SecureRandom random = new SecureRandom();
byte bytes[] = new byte[20];
random.nextBytes(bytes);
byte[] saltBytes = bytes;
// Derive the key
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), saltBytes, 65556, 256);
SecretKey secretKey = factory.generateSecret(spec);
SecretKeySpec secret = new SecretKeySpec(secretKey.getEncoded(), "AES");
System.out.println("saltBytes : " + saltBytes);
// encrypting the word
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
System.out.println("ivBytes : " + ivBytes);
byte[] encryptedTextBytes = cipher.doFinal(item.getBytes("UTF-8"));
// prepend salt and vi
byte[] buffer = new byte[saltBytes.length + ivBytes.length + encryptedTextBytes.length];
System.arraycopy(saltBytes, 0, buffer, 0, saltBytes.length);
System.arraycopy(ivBytes, 0, buffer, saltBytes.length, ivBytes.length);
System.arraycopy(encryptedTextBytes, 0, buffer, saltBytes.length + ivBytes.length, encryptedTextBytes.length);
return new Base64().encodeToString(buffer);
}
public String decrypt(String encryptedText) throws Exception {
String password = "Hello";
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
// strip off the salt and iv
ByteBuffer buffer = ByteBuffer.wrap(new Base64().decode(encryptedText));
byte[] saltBytes = new byte[20];
buffer.get(saltBytes, 0, saltBytes.length);
byte[] ivBytes1 = new byte[cipher.getBlockSize()];
buffer.get(ivBytes1, 0, ivBytes1.length);
byte[] encryptedTextBytes = new byte[buffer.capacity() - saltBytes.length - ivBytes1.length];
buffer.get(encryptedTextBytes);
// Deriving the key
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), saltBytes, 65556, 256);
SecretKey secretKey = factory.generateSecret(spec);
SecretKeySpec secret = new SecretKeySpec(secretKey.getEncoded(), "AES");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(ivBytes1));
byte[] decryptedTextBytes = null;
try {
decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return new String(decryptedTextBytes);
}
}
Dart implementation for decryption is something like this
class EncryptionHelper {
static String decrypt(
String ciphertext,
) {
Uint8List ciphertextlist = base64.decode(ciphertext);
var salt = ciphertextlist.sublist(0, 20);
var iv = ciphertextlist.sublist(20, 20 + 16);
var encrypted = ciphertextlist.sublist(20 + 16);
Uint8List key = generateKey("Hello", salt);
CBCBlockCipher cipher = new CBCBlockCipher(new AESFastEngine());
ParametersWithIV<KeyParameter> params =
new ParametersWithIV<KeyParameter>(new KeyParameter(key), iv);
PaddedBlockCipherParameters<ParametersWithIV<KeyParameter>, Null>
paddingParams =
new PaddedBlockCipherParameters<ParametersWithIV<KeyParameter>, Null>(
params, null);
PaddedBlockCipherImpl paddingCipher =
new PaddedBlockCipherImpl(new PKCS7Padding(), cipher);
paddingCipher.init(false, paddingParams);
var val = paddingCipher.process(encrypted);
return new String.fromCharCodes(val);
}
static Uint8List generateKey(String passphrase, Uint8List salt) {
Uint8List passphraseInt8List = Uint8List.fromList(passphrase.codeUnits);
KeyDerivator derivator =
PBKDF2KeyDerivator(HMac(SHA1Digest(), 64)); // 64 byte block size
Pbkdf2Parameters params =
Pbkdf2Parameters(salt, 65556, 32); // 32 byte key size
derivator.init(params);
return derivator.process(passphraseInt8List);
}
}
Why don't you use pointcastle ?
it is a dart porting of Bouncy castle and, as I can read in their page, there is yet the implementation of the AES algorithm for decrypt/encrpyt.
Moreover use :
https://pub.dev/packages/encrypt
that is a convenient wrapper on top of pointcastle.

How to decrypt aes-256-cbc in Java

I have encrypted the string in php. Decrypted successfully from php and node.js. In addition, it must be decrypted by java.
Help me an example of decrypting from java?
PHP Encrypt code
/* encrypt */
$encryption_method = 'aes-256-cbc';
$secretHash = "d95acd54c6a821ff32c52825b931c194";
$iv_size = openssl_cipher_iv_length($encryption_method);
$iv = openssl_random_pseudo_bytes($iv_size);
//encrypt
$encryptedMessage = openssl_encrypt($new_token, $encryption_method, $secretHash, 0, $iv);
//Concatenate iv with data
$ciphertext = bin2hex($iv).$encryptedMessage;
/* decrypt the cipher */
$iv_size = openssl_cipher_iv_length($encryptionMethod);
$iv = hex2bin(substr($encryptedMessageWithIv, 0, $iv_size * 2));
$decryptedMessage = openssl_decrypt(substr($encryptedMessageWithIv, $iv_size * 2), $encryptionMethod, $secretHash, 0, $iv);
Below is the encryption and decryption process for a string using AES algorithm.
private static final String key = "aesEncryptionKey";
private static final String initVector = "encryptionIntVec";
public static String encrypt(String value) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = cipher.doFinal(value.getBytes());
return Base64.encodeBase64String(encrypted);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static String decrypt(String encrypted) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));
return new String(original);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
In case init vector is not known, try using below code segment.
public byte[] decrypt(String encryptedString) throws DataLengthException, InvalidCipherTextException {
byte[] input = encryptedString.getBytes("UTF-8");
CBCBlockCipher cbcBlockCipher = new CBCBlockCipher(new AESEngine());
SecureRandom random = new SecureRandom();;
KeyParameter key = new KeyParameter("$secretHash".getBytes());// your key string
BlockCipherPadding blockCipherPadding = new PKCS7Padding();;
PaddedBufferedBlockCipher pbbc = new PaddedBufferedBlockCipher(cbcBlockCipher, blockCipherPadding);
int blockSize = cbcBlockCipher.getBlockSize(); // Make sure this block size is same as that used while encrypting the string.
int inputOffset = 0;
int inputLength = input.length;
int outputOffset = 0;
byte[] initializationVector = new byte[blockSize];
System.arraycopy(input, 0, initializationVector, 0, blockSize);
inputOffset += blockSize;
inputLength -= blockSize;
pbbc.init(encrypt, new ParametersWithIV(key, initializationVector));
byte[] output = new byte[pbbc.getOutputSize(inputLength) + outputOffset];
int outputLength = outputOffset + pbbc.processBytes(input, inputOffset, inputLength, output, outputOffset);
outputLength += pbbc.doFinal(output, outputLength);
return Arrays.copyOf(output, outputLength);
}
Just in case it helps someone in the future: encryption with AES/CBC/PKCS5PADDING along with the generation of a dynamic IV that is appended to the final ciphertext in Java can be done through the following code:
Encryption (JAVA)
public String encryptPlainText(String plainText) {
String cipherText = "";
try {
String keyString = "examplesecretkeyexamplesecretkey";
//Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy
Security.setProperty("crypto.policy", "unlimited");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
SecretKeySpec keyspec = new SecretKeySpec(keyString.getBytes(), "AES");
byte[] v = new byte[16];
new SecureRandom().nextBytes(v);
IvParameterSpec iv = new IvParameterSpec(v);
cipher.init(Cipher.ENCRYPT_MODE, keyspec, iv);
byte[] cipherTextByteArray = cipher.doFinal(plainText.getBytes());
//appending iv to ciphertext without any additional libraries to handle the concatenation of the two byte arrays
byte[] ivWithCipherTextByteArray = new byte[v.length + cipherTextByteArray.length];
System.arraycopy(v, 0, ivWithCipherTextByteArray, 0, v.length);
System.arraycopy(cipherTextByteArray, 0, ivWithCipherTextByteArray, v.length, cipherTextByteArray.length);
cipherText = new String(Base64.getEncoder().encode(ivWithCipherTextByteArray));
} catch (Exception e) {
LOG.info("Exception", e);
}
return cipherText;
}
Decryption of the cipherText obtained with the code above can be implemented in the following way:
Decryption (JAVA)
public static String decryptCipherText(String cipherText) {
String plainText="";
try {
String keyString = "examplesecretkeyexamplesecretkey";
Security.setProperty("crypto.policy", "unlimited");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
SecretKeySpec keyspec = new SecretKeySpec(keyString.getBytes(), "AES");
byte[] cipherTextByteArray = Base64.getDecoder().decode(cipherText);
//initialize the IvParameterSpec with the first 16 bytes of the cipherText
IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(cipherTextByteArray, 0, 16));
//cipherText to decrypt is now the original one with the first 16 bytes removed (the IV used above)
cipherTextByteArray = Arrays.copyOfRange(cipherTextByteArray, 16, cipherTextByteArray.length);
cipher.init(Cipher.DECRYPT_MODE, keyspec, iv);
plainText = new String(cipher.doFinal(cipherTextByteArray));
} catch (Exception e) {
LOG.info("Exception", e);
}
return plainText;
}

encrypt in Android and decrypt in CryptoJS

Hi I have java code which decrypt the ciphertext encrypted using CryptoJS library(AES).
Now i wanted to write the javacode which will encrypt the plaintext again.
Please find the below code.
try {
String secret = "René Über";
String cipherText="U2FsdGVkX1+tsmZvCEFa/iGeSA0K7gvgs9KXeZKwbCDNCs2zPo+BXjvKYLrJutMK+hxTwl/hyaQLOaD7LLIRo2I5fyeRMPnroo6k8N9uwKk=";
byte[] cipherData = Base64.decode(cipherText, Base64.DEFAULT);
byte[] saltData = Arrays.copyOfRange(cipherData, 8, 16);
MessageDigest md5 = MessageDigest.getInstance("MD5");
final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes("utf-8"), md5);
SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");
IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);
byte[] encrypted = Arrays.copyOfRange(cipherData, 16, cipherData.length);
Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");
aesCBC.init(Cipher.DECRYPT_MODE, key, iv);
byte[] decryptedData = aesCBC.doFinal(encrypted);
String decryptedText = new String(decryptedData,"utf-8");
System.out.println("Decrypted "+decryptedText);
//Here I get right plain text as
//System.out: Decrypted The quick brown fox jumps over the lazy dog.
Cipher abc=Cipher.getInstance("AES/CBC/PKCS5Padding");
abc.init(Cipher.ENCRYPT_MODE,key,iv);
byte[] encryptedData=abc.doFinal(decryptedData);
String str=Base64.encodeToString(encryptedData,Base64.DEFAULT);
System.out.println("encrypted "+str);
//Here i want the encrypted text as
// encrypted U2FsdGVkX1+tsmZvCEFa/iGeSA0K7gvgs9KXeZKwbCDNCs2zPo+BXjvKYLrJutMK+hxTwl/hy//aQLOaD7LLIRo2I5fyeRMPnroo6k8N9uwKk=
//but i receive
//System.out: encrypted IZ5IDQruC+Cz0pd5krBsIM0KzbM+j4FeO8pgusm60wr6HFPCX+HJpAs5oPssshGjYjl/J5Ew+//eui
}catch (Exception e)
{}
When I decrypt the code I get correct Plain Text but when I again encrypt the plain text I didnt get the encrypted text as previous.
Please Help.
GenerateKeyAndIV function code:-
public static byte[][] GenerateKeyAndIV(int keyLength, int ivLength, int iterations, byte[] salt, byte[] password, MessageDigest md) {
int digestLength = md.getDigestLength();
int requiredLength = (keyLength + ivLength + digestLength - 1) / digestLength * digestLength;
byte[] generatedData = new byte[requiredLength];
int generatedLength = 0;
try {
md.reset();
// Repeat process until sufficient data has been generated
while (generatedLength < keyLength + ivLength) {
// Digest data (last digest if available, password data, salt if available)
if (generatedLength > 0)
md.update(generatedData, generatedLength - digestLength, digestLength);
md.update(password);
if (salt != null)
md.update(salt, 0, 8);
md.digest(generatedData, generatedLength, digestLength);
// additional rounds
for (int i = 1; i < iterations; i++) {
md.update(generatedData, generatedLength, digestLength);
md.digest(generatedData, generatedLength, digestLength);
}
generatedLength += digestLength;
}
// Copy key and IV into separate byte arrays
byte[][] result = new byte[2][];
result[0] = Arrays.copyOfRange(generatedData, 0, keyLength);
if (ivLength > 0)
result[1] = Arrays.copyOfRange(generatedData, keyLength, keyLength + ivLength);
return result;
} catch (DigestException e) {
throw new RuntimeException(e);
} finally {
// Clean out temporary data
Arrays.fill(generatedData, (byte)0);
}
}
Your ciphertext has "Salted__<8 byte salt>" at the beginning, which you skip when decrypting. You need to prefix the same in your encryption mode if you want to create OpenSSL compatible ciphertext.
Your encryption code ciphertext seems correct when you view it in a base64 to hex decoder, e.g. the one provided here. However, because each character only contains 64 bits and since the bytes have shifted 16 places (which is not divisible by 3), it just seams that your entire ciphertext is incorrect, while it is just missing 16 bytes at the front.
Here posting my working code for android I have used crypto for decryption on the server. Below code is using AES Algorithm
private static final String key = "aesExamplekey";
private static final String initVector = "exampleintvec";
public static String encrypt(String value) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = cipher.doFinal(value.getBytes());
// byte[] finalCiphertext = new byte[encrypted.length+2*16];
return Base64.encodeToString(encrypted, Base64.NO_WRAP);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}`
Server side code asp.net
public string DecryptStringAES(string cipherText)
{
// var keybytes = Encoding.UTF8.GetBytes("7061737323313233");
// var iv = Encoding.UTF8.GetBytes("7061737323313233");
var keybytes = Encoding.UTF8.GetBytes("aesExamplekey");
var iv = Encoding.UTF8.GetBytes("exampleintvec");
var encrypted = Convert.FromBase64String(cipherText);
var decriptedFromJavascript = DecryptStringFromBytes(encrypted, keybytes, iv);
return string.Format(decriptedFromJavascript);
}

C# to Java TripleDES , different results

I'm attempting to convert this C# encryption algorithm to Java; however, I keep retrieving slightly different encrypted results (haven't tried decryption yet). It may also be important to point out that I'm not able to change the C# code.
However when I call the encrypt function in C# on the string "test" it will return nmj8MjjO52y928Syqf0J+g== However in Java it'll return C6xyQjJCqVo=
The C#
private static String key = "012345678901234567890123";
public static string encrypt(String stringToEncrypt)
{
TripleDES des = CreateDES(key);
ICryptoTransform ct = des.CreateEncryptor();
byte[] input = Encoding.Unicode.GetBytes(stringToEncrypt);
byte[] output = ct.TransformFinalBlock(input, 0, input.Length);
//return output;
return Convert.ToBase64String(output);
}
public static String decrypt(string encryptedString)
{
byte[] input = Convert.FromBase64String(encryptedString);
TripleDES des = CreateDES(key);
ICryptoTransform ct = des.CreateDecryptor();
byte[] output = ct.TransformFinalBlock(input, 0, input.Length);
return Encoding.Unicode.GetString(output);
}
public static TripleDES CreateDES(string key)
{
MD5 md5 = new MD5CryptoServiceProvider();
TripleDES des = new TripleDESCryptoServiceProvider();
des.Key = md5.ComputeHash(Encoding.Unicode.GetBytes(key));
des.IV = new byte[des.BlockSize / 8];
return des;
}
My Attempt with converting to Java
private static String key = "012345678901234567890123";
public static void main(String[] args) throws Exception {
String text = "test";
String codedtext = encrypt(text);
//String decodedtext = decrypt(codedtext);
System.out.println(new String(codedtext));
//System.out.println(decodedtext);
}
public static String encrypt(String message) throws Exception {
MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key.getBytes("unicode"));
byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
//for (int j = 0, k = 16; j < 8;) {
// keyBytes[k++] = keyBytes[j++];
//}
SecretKey key = new SecretKeySpec(keyBytes, "DESede");
IvParameterSpec iv = new IvParameterSpec(new byte[8]);
Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, iv);
byte[] plainTextBytes = message.getBytes();
byte[] cipherText = cipher.doFinal(plainTextBytes);
String output = Base64.encode(cipherText);
return output;
}
public static String decrypt(String message) throws Exception {
byte[] messageBytes = Base64.decode(message);
MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key.getBytes());
byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
SecretKey key = new SecretKeySpec(keyBytes, "DESede");
IvParameterSpec iv = new IvParameterSpec(new byte[8]);
Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
decipher.init(Cipher.DECRYPT_MODE, key, iv);
byte[] plainText = decipher.doFinal(messageBytes);
return new String(plainText);
}
Does anyone see what I'm overseeing?
You are missing two things. You are using a 16 length key on the c# side since it is not padded like the Java version. By default if the key is 16 bytes in length it will be padded with the first 8 bytes of the key.
To make this match on the Java side you will have to uncomment that line that adds the padding to the key:
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
SecretKey secretKey = new SecretKeySpec(keyBytes, 0, 24, "DESede");
Also, on the java side there was a suggestion to make sure to use UTF-LE for the text. Make sure to use it for everything. So the lines:
byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));
byte[] plainTextBytes = clearText.getBytes("UTF-16LE");
In general I would make sure to set the c# params of all the tripledes object, and not depend on defaults.
Here are two versions that match in c# and java
Java
String key = "012345678901234567890123";
String clearText = "test";
MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));
byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
String byteText = Arrays.toString(keyBytes);
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
SecretKey secretKey = new SecretKeySpec(keyBytes, 0, 24, "DESede");
IvParameterSpec iv = new IvParameterSpec(new byte[8]);
Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
byte[] plainTextBytes = clearText.getBytes("UTF-16LE");
byte[] cipherText = cipher.doFinal(plainTextBytes);
String output = Base64.encode(cipherText);
c#
string clearText = "test";
string key = "012345678901234567890123";
string encryptedText = "";
MD5 md5 = new MD5CryptoServiceProvider();
TripleDES des = new TripleDESCryptoServiceProvider();
des.KeySize = 128;
des.Mode = CipherMode.CBC;
des.Padding = PaddingMode.PKCS7;
byte[] md5Bytes = md5.ComputeHash(Encoding.Unicode.GetBytes(key));
byte[] ivBytes = new byte[8];
des.Key = md5Bytes;
des.IV = ivBytes;
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
ICryptoTransform ct = des.CreateEncryptor();
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(clearBytes, 0, clearBytes.Length);
cs.Close();
}
encryptedText = Convert.ToBase64String(ms.ToArray());
}
Edited: Both versions now return the test case result "nmj8MjjO52y928Syqf0J+g=="

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