rc4 encryption and decryption in java - java

I have tried working on the RC4 encryption and decryption procedure. I keep getting an error with the code line s2=key.charAt(j++).
The debugger tells me that it cannot be resolved from char to int.
The output runs untill entering the keystream. The XOR operation is not working out.
Can anyone point out a possible solution?
import java.util.Scanner;
public class Rc4
{
//global
public static int SIZE=256;
public static int[] s1 = new int[SIZE+1]; //filled with random numbers
public static int[] s2 = new int[SIZE+1]; //filled with keytext
public static int i,j;
public static String key, input;
public static void main(String[] args)
{
Scanner keyboard= new Scanner(System.in);
System.out.print("En/Decrypt:");
input = keyboard.nextLine();
System.out.print("Enter key :");
key = keyboard.nextLine();
INIT();
KSA();
}
static void INIT()
{
j=0;
for(i=0; i<SIZE; i++)
{
if(j==key.length())
j=0;
s2= key.charAt(j++);
}
}
static void KSA()
{
for( i=0; i<SIZE; i++)
s1[i]=i;
j=0;
for(int i=0; i<SIZE; i++)
{
j = (j + s1[i] + s2[i]) % SIZE;
swap(i, j);
}
}
static void PRGA()
{
int Rand=0;
//print();
j=i=0;
for(int x = 0; x< input.length(); x++)
{
i = (i + 1) % SIZE;
j = (j + s1[i]) % SIZE;
swap(i, j);
Rand = (char)s1[ ((s1[i] + s1[j]) % SIZE)];
System.out.print((char)(input.charAt(x) ^ Rand) );
}
}
static void print()
{
System.out.print("\n");
for(int y=0; y<input.length(); y++)
{
System.out.print(input.charAt(y));
}
System.out.print("\n");
}
static void swap(int i, int j)
{
int temp = s1[i];
s1[i]= s1[j];
s1[j] = temp;
}
}

You can use Hex and binary conversion of org.bouncycastle api for achieving the conversions without encoding issues. Built in crypto api can do the encryption/decryption for you.
Something like this:
import java.io.IOException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
import org.apache.commons.codec.DecoderException;
import org.bouncycastle.util.encoders.Hex;
public class RC4Algo {
public static void main(String args[])throws IOException, NoSuchAlgorithmException, DecoderException, InvalidKeyException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException
{
decryptRC4();
}
static String decryptRC4() throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException{
byte[] plainBytes = "testString".getBytes();
String hashedKey = hashedData("thisismysecretkey");
//Generate a new key using KeyGenerator
/*KeyGenerator rc4KeyGenerator = KeyGenerator.getInstance("RC4");
SecretKey key = rc4KeyGenerator.generateKey();*/
Key key = new SecretKeySpec(Hex.decode(hashedKey), "RC4"); //String to key conversion using Hex.decode to convert to byte []
// Create Cipher instance and initialize it to encrytion mode
Cipher cipher = Cipher.getInstance("RC4"); // Transformation of the algorithm
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] cipherBytes = cipher.doFinal(plainBytes);
String encoded = encodeBase64(cipherBytes);
String decoded = decodeBase64(encoded);
// Reinitialize the Cipher to decryption mode
cipher.init(Cipher.DECRYPT_MODE,key, cipher.getParameters());
byte[] plainBytesDecrypted = cipher.doFinal(Hex.decode(decoded));
System.out.println("Decrypted Data : "+new String(plainBytesDecrypted));
return new String(plainBytesDecrypted);
}
static String decodeBase64(String encodedData){
byte[] b = Base64.getDecoder().decode(encodedData);
String decodedData = DatatypeConverter.printHexBinary(b);
return decodedData;
}
static String encodeBase64(byte[] data){
byte[] b = Base64.getEncoder().encode(data);
String encodedData = new String(b);
/*String encodedData = DatatypeConverter.printHexBinary(b);*/
return encodedData;
}
static String hashedData(String key) throws NoSuchAlgorithmException{
String password = key;
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(password.getBytes());
byte byteData[] = md.digest();
//convert the byte to hex format method 1
StringBuffer sb = new StringBuffer();
for (int i = 0; i < byteData.length; i++) {
sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
}
//convert the byte to hex format method 2
StringBuffer hexString = new StringBuffer();
for (int i=0;i<byteData.length;i++) {
String hex=Integer.toHexString(0xff & byteData[i]);
if(hex.length()==1) hexString.append('0');
hexString.append(hex);
}
return hexString.toString();
}
}
Tip: Use Hex to binary and vice versa conversions to get rid of encoding issues.
Output:
Hope this helps!

RC4 is a byte-oriented algorithm. Java characters are not bytes. But you can convert strings to and from byte arrays as needed. You're welcome to check out my implementation here.
For the conversion to a string with UTF-8 encoding:
new String(bytes, "UTF-8");
and to a byte array:
str.getBytes("UTF-8");
or use a CharsetEncoder if you're not using a simple encoding like UTF-8.

Related

AES/CBC/PKCS5Padding Encryption result different in PHP and Java

I am developing a REST API in which the data to be passed to the server need to be encrypted with 'AES/CBC/PKCS5Padding'. The REST API client side is using Java to encrypt and decrypt the data, while on my side I am using PHP.
The secret key used here is hash with sha1. I have the same secret key value with the client side and also the IV value is the same, but when I try to encrypt and compare it to the client, it's different.
JAVA Code:
import java.util.Arrays;
import java.security.*;
import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.lang.Object;
class Main {
public static String stringToHex(String base)
{
StringBuffer buffer = new StringBuffer();
int intValue;
for(int x = 0; x < base.length(); x++)
{
int cursor = 0;
intValue = base.charAt(x);
String binaryChar = new String(Integer.toBinaryString(base.charAt(x)));
for(int i = 0; i < binaryChar.length(); i++)
{
if(binaryChar.charAt(i) == '1')
{
cursor += 1;
}
}
if((cursor % 2) > 0)
{
intValue += 128;
}
buffer.append(Integer.toHexString(intValue) + " ");
}
return buffer.toString();
}
public static String bytesToHex(byte[] a) {
StringBuilder sb = new StringBuilder(a.length * 2);
for(byte b: a)
sb.append(String.format("%02x", b));
return sb.toString();
}
public static void main(String[] args) throws NoSuchAlgorithmException, UnsupportedEncodingException,
InvalidAlgorithmParameterException,
NoSuchProviderException,
NoSuchPaddingException,
InvalidKeyException,
IllegalBlockSizeException,
BadPaddingException
{
MessageDigest sha = MessageDigest.getInstance("SHA-1");
String secretKey = "mysecretkey102018";
String message = "00155001C"
byte[] key = sha.digest(secretKey.getBytes("UTF-8"));
byte[] value = message.getBytes();
key = Arrays.copyOf(key, 16);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
IvParameterSpec iv = new IvParameterSpec("AAAAAAAAAAAAAAAA".getBytes("UTF-8"));
cipher.init(Cipher.ENCRYPT_MODE, keySpec, iv);
System.out.println(bytesToHex(cipher.doFinal(value)));
}
PHP Code:
class IDebit
{
private $iv = "AAAAAAAAAAAAAAAA";
private $secret_key = "mysecretkey102018";
private $message = "00155001C";
public function generateEncrytedKeyId()
{
$hashPassword = substr(hash("SHA1", $secret_key), 0, 32);
$blocksize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$str = $this->pkcs5_pad($message, $blocksize);
$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $hashPassword, $str, MCRYPT_MODE_CBC, self::IV);
return bin2hex($encrypted);
}
protected function pkcs5_pad($text, $blocksize)
{
$pad = $blocksize - (strlen($text) % $blocksize);
return $text . str_repeat(chr($pad), $pad);
}
}
The encryption result on Java is c1e7af770d9d0af59cc75d1c76aa78f6, while on PHP is d67a15a027be7e7ab68ea6ab88ea4f2f
I'm wondering what is wrong with my code. I have googled and check on this forum about the question dozens of times but I am unable to get the same result. I have rechecked my code with the answers posted by people on this forum and it's identical.

Encryption and decryption using RC4 [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 4 years ago.
Improve this question
I am trying to write a code for encryption and decryption input text with RC4 in Java. Does anyone know how to fix it?
My code:
import java.util.Arrays;
public class RC4 {
private static final int SBOX_LEN = 256;
private static final int MIN_KEY_LEN = 5;
private byte[] key = new byte[SBOX_LEN - 1];
private int[] sbox = new int[SBOX_LEN];
public RC4() {
initialize();
}
public RC4(String key) {
this();
setKey(key);
}
public static void main(String[] args) {
RC4 rc4 = new RC4();
byte[] cipherText = rc4.encryptMessage(args[0], args[1]);
System.out.println(Arrays.toString(cipherText));
String plainText = rc4.decryptMessage(cipherText, args[1]);
System.out.println(plainText);
}
private void initialize() {
Arrays.fill(key, (byte) 0);
Arrays.fill(sbox, 0);
}
public byte[] encryptMessage(String message, String key) {
initialize();
setKey(key);
byte[] crypt = crypt(message.getBytes());
initialize();
return crypt;
}
public String decryptMessage(byte[] message, String key) {
initialize();
setKey(key);
byte[] msg = crypt(message);
initialize();
return new String(msg);
}
public byte[] crypt(final byte[] msg) {
sbox = initializeSBox(key);
byte[] code = new byte[msg.length];
int i = 0;
int j = 0;
for (int n = 0; n < msg.length; n++) {
i = (i + 1) % SBOX_LEN;
j = (j + sbox[i]) % SBOX_LEN;
swap(i, j, sbox);
int rand = sbox[(sbox[i] + sbox[j]) % SBOX_LEN];
code[n] = (byte) (rand ^ msg[n]);
}
return code;
}
private int[] initializeSBox(byte[] key) {
int[] sbox = new int[SBOX_LEN];
int j = 0;
for (int i = 0; i < SBOX_LEN; i++) {
sbox[i] = i;
}
for (int i = 0; i < SBOX_LEN; i++) {
j = ((j + sbox[i] + (key[i % key.length])) & 0xFF) % SBOX_LEN;
swap(i, j, sbox);
}
return sbox;
}
private void swap(int i, int j, int[] sbox) {
int temp = sbox[i];
sbox[i] = sbox[j];
sbox[j] = temp;
}
public void setKey(String key) {
if (!((key.length() >= MIN_KEY_LEN) && (key.length() < SBOX_LEN))) {
throw new RuntimeException(String.format("Key length must be between %d and %d", MIN_KEY_LEN, SBOX_LEN - 1));
}
this.key = key.getBytes();
}
}
RC4 is a broken algorithm and recommendation is to not use the same anymore if the data is to be kept highly secure.
If you still need a working implementation, you don't need to recreate the algorithm in your code. Java API javax.crypto can do it for you. Just generate a key and call the init method with mode set to encryption/decryption.
static String decryptRC4() throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException{
byte[] testDataBytes = "testString".getBytes();
KeyGenerator rc4KeyGenerator = KeyGenerator.getInstance("RC4");
SecretKey key = rc4KeyGenerator.generateKey();
// Create Cipher instance and initialize it to encrytion mode
Cipher cipher = Cipher.getInstance("RC4"); // Transformation of the algorithm
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] cipherBytes = cipher.doFinal(testDataBytes);
// Reinitialize the Cipher to decryption mode
cipher.init(Cipher.DECRYPT_MODE,key, cipher.getParameters());
byte[] testDataBytesDecrypted = cipher.doFinal(cipherBytes);
System.out.println("Decrypted Data : "+new String(testDataBytesDecrypted));
return new String(testDataBytesDecrypted);
}
Output:
If you need to send the encrypted data as part of a url then use Base64Encoding and then send.
e.g.
static String decryptRC4() throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException{
byte[] plainBytes = "testString".getBytes();
KeyGenerator rc4KeyGenerator = KeyGenerator.getInstance("RC4");
SecretKey key = rc4KeyGenerator.generateKey();
// Create Cipher instance and initialize it to encrytion mode
Cipher cipher = Cipher.getInstance("RC4"); // Transformation of the algorithm
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] cipherBytes = cipher.doFinal(plainBytes);
String encoded = encodeBase64(cipherBytes);
String decoded = decodeBase64(encoded);
// Reinitialize the Cipher to decryption mode
cipher.init(Cipher.DECRYPT_MODE,key, cipher.getParameters());
byte[] plainBytesDecrypted = cipher.doFinal(Hex.decode(decoded));
System.out.println("Decrypted Data : "+new String(plainBytesDecrypted));
return new String(plainBytesDecrypted);
}
static String decodeBase64(String encodedData){
byte[] b = Base64.getDecoder().decode(encodedData);
String decodedData = DatatypeConverter.printHexBinary(b);
return decodedData;
}
static String encodeBase64(byte[] data){
byte[] b = Base64.getEncoder().encode(data);
String encodedData = new String(b);
/*String encodedData = DatatypeConverter.printHexBinary(b);*/
return encodedData;
}
** Tip: ** Use Hex.decode as shown above to get bytes from the base64 decoded string or else you will get encoding issues. As much as possible do the conversions using Hex and convert to bytes array using bouncycastle methods.
Imports needed:
import java.io.IOException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.xml.bind.DatatypeConverter;
import org.apache.commons.codec.DecoderException;
import org.bouncycastle.util.encoders.Hex;
Also if you are generating a key from your own string you can use MD5Hashing for the same.

How do I generate a hash code with hash sha256 in java?

I would like to know the code to do this in java please?
This is what i have so far but it does not work?
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import static jdk.nashorn.tools.ShellFunctions.input;
public class Sha256hash
{
public static String main(String[] args) throws NoSuchAlgorithmException
{
MessageDigest md = MessageDigest.getInstance("SHA1");
md.reset();
byte[] buffer = input.getBytes("UTF-8");
md.update(buffer);
byte[] digest = md.digest();
String hexStr = "";
for (int i = 0; i < digest.length; i++) {
hexStr += Integer.toString( ( digest[i] & 0xff ) + 0x100, 16).substring( 1 );
}
return hexStr;
}
}
I'm still unclear whether you want SHA-1 or SHA-256, so let's abstract the problem; firstly, an encode method to take a byte[] and return the hex (don't worry, you already wrote it; but I would prefer a StringBuilder over String concatenation. Java String is immutable, so you're creating garbage for later garbage collection with +) -
private static String encodeHex(byte[] digest) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < digest.length; i++) {
sb.append(Integer.toString((digest[i] & 0xff) + 0x100, 16).substring(1));
}
return sb.toString();
}
Next, we can create a method that takes the algorithm name and the String to digest and returns that digest. Like
public static String digest(String alg, String input) {
try {
MessageDigest md = MessageDigest.getInstance(alg);
byte[] buffer = input.getBytes("UTF-8");
md.update(buffer);
byte[] digest = md.digest();
return encodeHex(digest);
} catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
e.printStackTrace();
return e.getMessage();
}
}
Then we can get a SHA-1 or a SHA-256 hash like
public static void main(String[] args) {
System.out.println(digest("SHA1", ""));
System.out.println(digest("SHA-256", ""));
}
Which outputs (as expected)
da39a3ee5e6b4b0d3255bfef95601890afd80709
e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
The main entry point can not return String. Furthermore, input is not declared. You maybe want to change the name of your function to generate with input as a parameter.
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import static jdk.nashorn.tools.ShellFunctions.input;
public class Sha256hash
{
public static String generate(String input) throws NoSuchAlgorithmException
{
MessageDigest md = MessageDigest.getInstance("SHA1");
md.reset();
byte[] buffer = input.getBytes("UTF-8");
md.update(buffer);
byte[] digest = md.digest();
String hexStr = "";
for (int i = 0; i < digest.length; i++) {
hexStr += Integer.toString( ( digest[i] & 0xff ) + 0x100, 16).substring( 1 );
}
return hexStr;
}
}
This example works for me returning c3499c2729730a7f807efb8676a92dcb6f8a3f8f as result of processing the string example:
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class Sha256hash
{
public static String generate(String input) throws NoSuchAlgorithmException, UnsupportedEncodingException
{
MessageDigest md = MessageDigest.getInstance("SHA1");
md.reset();
byte[] buffer = input.getBytes("UTF-8");
md.update(buffer);
byte[] digest = md.digest();
String hexStr = "";
for (int i = 0; i < digest.length; i++) {
hexStr += Integer.toString( ( digest[i] & 0xff ) + 0x100, 16).substring( 1 );
}
return hexStr;
}
}
Main:
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
public class Tester {
public static void main(String[] args) throws NoSuchAlgorithmException, UnsupportedEncodingException {
String someText = "example";
System.out.println(Sha256hash.generate(someText));
}
}
Finally, as Elliott has pointed out If you want to use SHA-256 you should change MessageDigest.getInstance("SHA1"); to MessageDigest.getInstance("SHA256"); Right now you are using SHA-1. Also pointed by Elliot you should use StringBuilder in the loop for improved efficiency.

RC4 Encryption/Decryption with C# and Java

I even use the AES algorithm to encrypt and decrypt files, but according to my research, the performance of this algorithm is slower than the RC4 algorithm in Java.
I'm use this code for encrypt files in C#
public static class RC4
{
public static byte[] Encrypt(byte[] key, byte[] data)
{
return EncryptOutput(key, data).ToArray();
}
private static byte[] EncryptInitalize(byte[] key)
{
byte[] s = Enumerable.Range(0, 256)
.Select(i => (byte)i)
.ToArray();
for (int i = 0, j = 0; i < 256; i++)
{
j = (j + key[i % key.Length] + s[i]) & 255;
Swap(s, i, j);
}
return s;
}
private static IEnumerable<byte> EncryptOutput(byte[] key, IEnumerable<byte> data)
{
byte[] s = EncryptInitalize(key);
int i = 0;
int j = 0;
return data.Select((b) =>
{
i = (i + 1) & 255;
j = (j + s[i]) & 255;
Swap(s, i, j);
return (byte)(b ^ s[(s[i] + s[j]) & 255]);
});
}
private static void Swap(byte[] s, int i, int j)
{
byte c = s[i];
s[i] = s[j];
s[j] = c;
}
}
I need to encrypt a file in C # and decrypt this file with java, but found no implementation for both languages.
This solution implemented by Michael Remijan showed better performance to decrypt files using AES. Encrypt and Decrypt files for I implemented just a string conversion to byte array.
Java Code
package org.ferris.aes.crypto;
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
/**
*
* #author Michael Remijan mjremijan#yahoo.com #mjremijan
*/
public class AesBase64Wrapper {
private static String IV = "IV_VALUE_16_BYTE";
private static String PASSWORD = "PASSWORD_VALUE";
private static String SALT = "SALT_VALUE";
public String encryptAndEncode(String raw) {
try {
Cipher c = getCipher(Cipher.ENCRYPT_MODE);
byte[] encryptedVal = c.doFinal(getBytes(raw));
String s = getString(Base64.encodeBase64(encryptedVal));
return s;
} catch (Throwable t) {
throw new RuntimeException(t);
}
}
public String decodeAndDecrypt(String encrypted) throws Exception {
byte[] decodedValue = Base64.decodeBase64(getBytes(encrypted));
Cipher c = getCipher(Cipher.DECRYPT_MODE);
byte[] decValue = c.doFinal(decodedValue);
return new String(decValue);
}
private String getString(byte[] bytes) throws UnsupportedEncodingException {
return new String(bytes, "UTF-8");
}
private byte[] getBytes(String str) throws UnsupportedEncodingException {
return str.getBytes("UTF-8");
}
private Cipher getCipher(int mode) throws Exception {
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] iv = getBytes(IV);
c.init(mode, generateKey(), new IvParameterSpec(iv));
return c;
}
private Key generateKey() throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
char[] password = PASSWORD.toCharArray();
byte[] salt = getBytes(SALT);
KeySpec spec = new PBEKeySpec(password, salt, 65536, 128);
SecretKey tmp = factory.generateSecret(spec);
byte[] encoded = tmp.getEncoded();
return new SecretKeySpec(encoded, "AES");
}
}
C# Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
namespace EncryptDecryptTest
{
class Program
{
class AesBase64Wrapper
{
private static string IV = "IV_VALUE_16_BYTE";
private static string PASSWORD = "PASSWORD_VALUE";
private static string SALT = "SALT_VALUE";
public static string EncryptAndEncode(string raw)
{
using (var csp = new AesCryptoServiceProvider())
{
ICryptoTransform e = GetCryptoTransform(csp, true);
byte[] inputBuffer = Encoding.UTF8.GetBytes(raw);
byte[] output = e.TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
string encrypted = Convert.ToBase64String(output);
return encrypted;
}
}
public static string DecodeAndDecrypt(string encrypted)
{
using (var csp = new AesCryptoServiceProvider())
{
var d = GetCryptoTransform(csp, false);
byte[] output = Convert.FromBase64String(encrypted);
byte[] decryptedOutput = d.TransformFinalBlock(output, 0, output.Length);
string decypted = Encoding.UTF8.GetString(decryptedOutput);
return decypted;
}
}
private static ICryptoTransform GetCryptoTransform(AesCryptoServiceProvider csp, bool encrypting)
{
csp.Mode = CipherMode.CBC;
csp.Padding = PaddingMode.PKCS7;
var spec = new Rfc2898DeriveBytes(Encoding.UTF8.GetBytes(PASSWORD), Encoding.UTF8.GetBytes(SALT), 65536);
byte[] key = spec.GetBytes(16);
csp.IV = Encoding.UTF8.GetBytes(IV);
csp.Key = key;
if (encrypting)
{
return csp.CreateEncryptor();
}
return csp.CreateDecryptor();
}
}
static void Main(string[] args)
{
string encryptMe;
string encrypted;
string decrypted;
encryptMe = "please encrypt me";
Console.WriteLine("encryptMe = " + encryptMe);
encrypted = AesBase64Wrapper.EncryptAndEncode(encryptMe);
Console.WriteLine("encypted: " + encrypted);
decrypted = AesBase64Wrapper.DecodeAndDecrypt(encrypted);
Console.WriteLine("decrypted: " + decrypted);
Console.WriteLine("press any key to exit....");
Console.ReadKey();
}
}
}
Based on your comments, I am assuming you want to know how to speed up your encryption / decryption process, and changing the main algorithm is not mandatory.
You could look at different modes for AES. For example, AES in counter (CTR) mode is significantly faster than cipher block chaining (CBC) which is often used.
Try creating your cipher like
Cipher myCipher = Cipher.getInstance("AES/CTR/NoPadding");
and you should see a performance increase. Additionally, using NoPadding will keep the size the same as the plaintext.
(Yes, I know that CTR mode turn AES into a stream cipher, never mind my comment)
UPDATE
I have used this in the past along these lines:
Key key = new SecretKeySpec(yourKeyValue, "AES");
Cipher enc = Cipher.getInstance("AES/CTR/NoPadding");
enc.init(Cipher.ENCRYPT_MODE, key);
// Get the IV that was generated
byte[] iv = enc.getIV();
// Encrypt your data
...
Cipher dec = Cipher.getInstance("AES/CTR/NoPadding");
dec.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
// Decrypt your data
...

CryptoJS AES encryption and JAVA AES decryption value mismatch

I am encrypting a text using CryptoJS AES algorithm on the client side and I am decrypting It on Server side in java, I am getting the exception.
JS code :
var encrypted = CryptoJS.AES.encrypt("Message", "Secret Passphrase");
console.info("encrypted " + encrypted);
var decrypted = CryptoJS.AES.decrypt(encrypted, "Secret Passphrase");
var plainText = decrypted.toString(CryptoJS.enc.Utf8)
console.info("decrypted " + plainText);
js output :
encrypted U2FsdGVkX1/uYgVsNZmpbgKQJ8KD+8R8yyYn5+irhoI=
decrypted Message
Java Code :
import java.nio.charset.Charset;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.util.regex.Pattern;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class AESJavaScript {
private SecretKeySpec key;
private Cipher cipher;
private int size = 128;
private static final Charset CHARSET = Charset.forName("UTF-8");
public AESJavaScript() throws NoSuchAlgorithmException,
NoSuchPaddingException, NoSuchProviderException {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(size); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
key = new SecretKeySpec(raw, "AES/CTR/NoPadding");
cipher = Cipher.getInstance("AES/CTR/NoPadding");
}
public void setKey(String keyText) {
byte[] bText = new byte[size];
bText = keyText.getBytes(CHARSET);
key = new SecretKeySpec(bText, "AES/CTR/NoPadding");
}
public String encrypt(String message) throws InvalidKeyException,
IllegalBlockSizeException, BadPaddingException {
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encrypted = cipher.doFinal(message.getBytes());
return byteArrayToHexString(encrypted);
}
public String decrypt(String hexCiphertext)
throws IllegalBlockSizeException, BadPaddingException,
InvalidKeyException {
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(hexStringToByteArray(hexCiphertext));
return byteArrayToHexString(decrypted);
}
private static String byteArrayToHexString(byte[] raw) {
String hex = "0x";
String s = new String(raw);
for (int x = 0; x < s.length(); x++) {
char[] t = s.substring(x, x + 1).toCharArray();
hex += Integer.toHexString((int) t[0]).toUpperCase();
}
return hex;
}
private static byte[] hexStringToByteArray(String hex) {
Pattern replace = Pattern.compile("^0x");
String s = replace.matcher(hex).replaceAll("");
byte[] b = new byte[s.length() / 2];
for (int i = 0; i < b.length; i++) {
int index = i * 2;
int v = Integer.parseInt(s.substring(index, index + 2), 16);
b[i] = (byte) v;
}
return b;
}
public static void main(String[] args) {
try {
AESJavaScript ajs = new AESJavaScript();
ajs.setKey("Secret Passphrase");
String hexCiphertext = "U2FsdGVkX1/uYgVsNZmpbgKQJ8KD+8R8yyYn5+irhoI=";
String decrypted = ajs.decrypt(hexCiphertext);
System.out.println("decrypted > " + decrypted);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Exception is :
java.security.InvalidKeyException: Invalid AES key length: 17 bytes
at com.sun.crypto.provider.AESCipher.engineGetKeySize(AESCipher.java:372)
at javax.crypto.Cipher.passCryptoPermCheck(Cipher.java:1052)
at javax.crypto.Cipher.checkCryptoPerm(Cipher.java:1010)
at javax.crypto.Cipher.implInit(Cipher.java:786)
at javax.crypto.Cipher.chooseProvider(Cipher.java:849)
at javax.crypto.Cipher.init(Cipher.java:1213)
at javax.crypto.Cipher.init(Cipher.java:1153)
at com.test.jenkins.jenkinsRestart.AESJavaScript.decrypt(AESJavaScript.java:49)
at com.test.jenkins.jenkinsRestart.AESJavaScript.main(AESJavaScript.java:82)
Is there anything that I am doing wrong here or Is there anyother simple way to do these kind of encryption and decryption ?
Your Java code is riddled with errors. Here are a few of them:
Your initial exception is caused because your "Secret Passphrase" string contains 17 bytes. You need to truncate this to 16 bytes (or pad it to match 24 or 32 bytes). You need to match the behaviour of the CryptoJS library.
You are trying to hex-decode data that appears to be base64 encoded. Try using DatatypeConverter.parseBase64Binary(hex);.
You are creating a secret key with the algorithm "AES/CTR/NoPadding". This in invalid, just use "AES".
You must pass an IV/nonce value into your decryption:
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(...));
The value you use will depend upon what CryptoJS is doing. Perhaps it uses all zeroes? Perhaps it generates a random one and you need to store it with the ciphertext?
This should be enough to get you started.

Categories

Resources