c# decryption [Java Encryption]

[EDN Admin]

Hi all,
Im pretty new to Encryption/Decryption and I have been struggling for the last 2 days trying to decrypt data encrypted in Java.
From my understanding, the following java code use DES mode ECB with PKCS5Padding for Padding.
The key is: 7IC64w6ksLU
The value to decode is: cy0vlmQq8RIc3lalnjPKpA==
The java encryption script is the following: import java.security.MessageDigest;

import java.util.Arrays;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.SecretKeyFactory;

import javax.crypto.spec.DESKeySpec;

import javax.crypto.spec.IvParameterSpec;

import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

import org.apache.commons.lang.StringUtils;





public String ALGORITHM = "DES/ECB/PKCS5Padding";

public String HASH_ALGORITHM = "SHA";



public String CHARSET = "UTF-8";



private SecretKey desKey;

private FieldHelper encrypted = null;



public boolean processRow(StepMetaInterface smi, StepDataInterface sdi) throws KettleException

{



Object[] r = getRow();



if (r == null) {

setOutputDone();

return false;

}



if (first){

first = false;

try {

setSecretKey("7IC64w6ksLU");

}

catch (Exception e) {

throw new RuntimeException(e);

}

}



r = createOutputRow(r, data.outputRowMeta.size());



// Get the value from an input field

String test_value = get(Fields.In, "vht_tax_number").getString(r);



// play around with it

if(test_value != null) {

String regexed=test_value.replaceAll("[^0-9]","");

String Encrypted = encrypt(regexed);



// Set a value in a new output field

get(Fields.Out, "encrypted").setValue(r, Encrypted);

} else {

get(Fields.Out, "encrypted").setValue(r, test_value);

}



// Send the row on to the next step.

putRow(data.outputRowMeta, r);



return true;

}

public String encrypt(Object valueToHide) {





if (valueToHide == null) {

return "";

}

try {

// Initialize the cipher for encryption

Cipher cipher = Cipher.getInstance(ALGORITHM);

cipher.init(Cipher.ENCRYPT_MODE, desKey);





// Our cleartext

byte[] cleartext = valueToHide.toString().getBytes(CHARSET);



// Encrypt the cleartext

byte[] ciphertext = cipher.doFinal(cleartext);



return new String(Base64.encodeBase64(ciphertext), CHARSET);

}

catch (Exception e) {

throw new RuntimeException(e);

}

}

private SecretKey unwrapEncodedKey(String key) throws Exception {

KeyGenerator keygen = KeyGenerator.getInstance("DES");

SecretKey desKey = keygen.generateKey();



// Create the cipher

Cipher cipher = Cipher.getInstance(ALGORITHM);

cipher.init((Cipher.UNWRAP_MODE), desKey);



byte[] bytes = Base64.decodeBase64(key.getBytes());



SecretKeyFactory desFactory = SecretKeyFactory.getInstance("DES");



DESKeySpec keyspec = new DESKeySpec(bytes);

SecretKey k = desFactory.generateSecret(keyspec);



return k;



}

public void setSecretKey(String secretKey) throws Exception {

if (!StringUtils.isEmpty(secretKey)) {

desKey = this.unwrapEncodedKey(secretKey);



// Create the cipher

Cipher cipher = Cipher.getInstance(ALGORITHM);

cipher.init((Cipher.WRAP_MODE), desKey);

}

}


My C# decryption code is the following:using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class ConsoleApplication3
{
static void Main(string[] args)
{
try
{
// Create a new TripleDESCryptoServiceProvider object
// to generate a key and initialization vector (IV).
DESCryptoServiceProvider tDESalg = new DESCryptoServiceProvider();
tDESalg.Mode = CipherMode.ECB;
//tDESalg.Padding = PaddingMode.PKCS7;
tDESalg.GenerateKey();
//byte[] key = tDESalg.Key;

//Console.Write("Generated key: n");
//foreach(byte b in key){
// Console.Write(b + "n");
//}

//Console.Write("nn");

tDESalg.Key = System.Convert.FromBase64String("71C64w6ksLU=");

// Decrypt the buffer back to a string.
string Final = DecryptTextFromMemory(System.Convert.FromBase64String("cy0vlmQq8RIc3lalnjPKpA=="), tDESalg.Key, tDESalg.IV);

// Display the decrypted string to the console.
Console.WriteLine(Final);
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}

}

public static string DecryptTextFromMemory(byte[] Data, byte[] Key, byte[] IV)
{
try
{
// Create a new MemoryStream using the passed
// array of encrypted data.
MemoryStream msDecrypt = new MemoryStream(Data);

// Create a CryptoStream using the MemoryStream
// and the passed key and initialization vector (IV).
CryptoStream csDecrypt = new CryptoStream(msDecrypt,
new DESCryptoServiceProvider().CreateDecryptor(Key, IV),
CryptoStreamMode.Read);


// Create buffer to hold the decrypted data.
byte[] fromEncrypt = new byte[Data.Length];

// Read the decrypted data out of the crypto stream
// and place it into the temporary buffer.
csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);

//Convert the buffer into a string and return it.
return new ASCIIEncoding().GetString(fromEncrypt);
//String res = System.Convert.ToBase64String(fromEncrypt);
//return res;
}
catch(CryptographicException e)
{
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
return null;
}
}
}
Please let me know if you have any suggestion for decrypting this value. I cant point out what I am doing wrong.
Regards,
Greg

View the full article