Rijndael on C# and Java

RijndaelCrypt.cs

#region Using
 
using System;
using System.Security.Cryptography;
using System.Text;
 
#endregion
 
namespace YourApp.Security.Cryptography
{
    /// <summary>
    /// Rijndael Encryptor / Decryptor Helper
    /// 
    /// <remarks>
    /// Created by: Jafet Sanchez 
    /// Last Update: [date],[author],[description]
    /// 
    public class RijndaelCrypt
    {
        #region Private/Protected Member Variables
         
        /// <summary>
        /// Decryptor
        /// 
        private readonly ICryptoTransform _decryptor;
 
        /// <summary>
        /// Encryptor
        /// 
        private readonly ICryptoTransform _encryptor;
 
        /// <summary>
        /// 16-byte Private Key
        /// 
        private static readonly byte[] IV = Encoding.UTF8.GetBytes("ThisIsUrPassword");
 
        /// <summary>
        /// Public Key
        /// 
        private readonly byte[] _password;
 
        /// <summary>
        /// Rijndael cipher algorithm
        /// 
        private readonly RijndaelManaged _cipher;
 
        #endregion
 
        #region Private/Protected Properties
 
        private ICryptoTransform Decryptor { get { return _decryptor; } }
        private ICryptoTransform Encryptor { get { return _encryptor; } }
 
        #endregion
 
        #region Private/Protected Methods
        #endregion
 
        #region Constructor
 
        /// <summary>
        /// Constructor
        /// 
        /// <param name="password">Public key
        public RijndaelCrypt(string password)
        {
            //Encode digest
            var md5 = new MD5CryptoServiceProvider();
            _password = md5.ComputeHash(Encoding.ASCII.GetBytes(password));
 
            //Initialize objects
            _cipher = new RijndaelManaged();
            _decryptor = _cipher.CreateDecryptor(_password, IV);
            _encryptor = _cipher.CreateEncryptor(_password, IV);
 
        }
 
        #endregion
 
        #region Public Properties
        #endregion
 
        #region Public Methods
 
        /// <summary>
        /// Decryptor
        /// 
        /// <param name="text">Base64 string to be decrypted
        /// <returns>
        public string Decrypt(string text)
        {
            try
            {
                byte[] input = Convert.FromBase64String(text);
 
                var newClearData = Decryptor.TransformFinalBlock(input, 0, input.Length);
                return Encoding.ASCII.GetString(newClearData);
            }
            catch (ArgumentException ae)
            {
                Console.WriteLine("inputCount uses an invalid value or inputBuffer has an invalid offset length. " + ae);
                return null;
            }
            catch (ObjectDisposedException oe)
            {
                Console.WriteLine("The object has already been disposed." + oe);
                return null;
            }
 
 
        }
 
        /// <summary>
        /// Encryptor
        /// 
        /// <param name="text">String to be encrypted
        /// <returns>
        public string Encrypt(string text)
        {
            try
            {
                var buffer = Encoding.ASCII.GetBytes(text);
                return Convert.ToBase64String(Encryptor.TransformFinalBlock(buffer, 0, buffer.Length));
            }
            catch (ArgumentException ae)
            {
                Console.WriteLine("inputCount uses an invalid value or inputBuffer has an invalid offset length. " + ae);
                return null;
            }
            catch (ObjectDisposedException oe)
            {
                Console.WriteLine("The object has already been disposed." + oe);
                return null;
            }
 
        }
 
        #endregion
    }
}

RijndaelCrypt.java

package com.yourpackage.security;
 
import android.util.Log;
import android.util.Base64;
 
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
 
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
 
public class RijndaelCrypt {
 
    public static final String TAG = "YourAppName";
 
    private static String TRANSFORMATION = "AES/CBC/PKCS7Padding";
    private static String ALGORITHM = "AES";
    private static String DIGEST = "MD5";
     
    private static Cipher _cipher;
    private static SecretKey _password;
    private static IvParameterSpec _IVParamSpec;
     
    //16-byte private key
    private static byte[] IV = "ThisIsUrPassword".getBytes();
     
     
    /**
     Constructor
     @password Public key
      
    */
    public RijndaelCrypt(String password) {
 
        try {
             
            //Encode digest
            MessageDigest digest;           
            digest = MessageDigest.getInstance(DIGEST);            
            _password = new SecretKeySpec(digest.digest(password.getBytes()), ALGORITHM);
             
            //Initialize objects
            _cipher = Cipher.getInstance(TRANSFORMATION);
            _IVParamSpec = new IvParameterSpec(IV);
             
        } catch (NoSuchAlgorithmException e) {
            Log.e(TAG, "No such algorithm " + ALGORITHM, e);
        } catch (NoSuchPaddingException e) {
            Log.e(TAG, "No such padding PKCS7", e);
        }              
    }
 
    /**
    Encryptor.
 
    @text String to be encrypted
    @return Base64 encrypted text
 
    */
    public String encrypt(byte[] text) {
         
        byte[] encryptedData;
         
        try {
             
            _cipher.init(Cipher.ENCRYPT_MODE, _password, _IVParamSpec);
            encryptedData = _cipher.doFinal(text);
             
        } catch (InvalidKeyException e) {
            Log.e(TAG, "Invalid key  (invalid encoding, wrong length, uninitialized, etc).", e);
            return null;
        } catch (InvalidAlgorithmParameterException e) {
            Log.e(TAG, "Invalid or inappropriate algorithm parameters for " + ALGORITHM, e);
            return null;
        } catch (IllegalBlockSizeException e) {
            Log.e(TAG, "The length of data provided to a block cipher is incorrect", e);
            return null;
        } catch (BadPaddingException e) {
            Log.e(TAG, "The input data but the data is not padded properly.", e);
            return null;
        }               
         
        return Base64.encodeToString(encryptedData,Base64.DEFAULT);
         
    }
     
    /**
    Decryptor.
 
    @text Base64 string to be decrypted
    @return decrypted text
 
    */   
    public String decrypt(String text) {
 
        try {
            _cipher.init(Cipher.DECRYPT_MODE, _password, _IVParamSpec);
             
            byte[] decodedValue = Base64.decode(text.getBytes(), Base64.DEFAULT);
            byte[] decryptedVal = _cipher.doFinal(decodedValue);
            return new String(decryptedVal);            
             
             
        } catch (InvalidKeyException e) {
            Log.e(TAG, "Invalid key  (invalid encoding, wrong length, uninitialized, etc).", e);
            return null;
        } catch (InvalidAlgorithmParameterException e) {
            Log.e(TAG, "Invalid or inappropriate algorithm parameters for " + ALGORITHM, e);
            return null;
        } catch (IllegalBlockSizeException e) {
            Log.e(TAG, "The length of data provided to a block cipher is incorrect", e);
            return null;
        } catch (BadPaddingException e) {
            Log.e(TAG, "The input data but the data is not padded properly.", e);
            return null;
        }               
         
    }
     
}

It was perfect. Thank a lot! I used it for connection between my Android App and C# Server.

Thx 👍

Another Thx :)

Another Thx :P

thanks men

I'm sorry, I'm new to programming and a little bit slow. I want to use this in Android (Java). So how exactly do you use this in LoginActivity? For simple example, say I only have EditText for password and Button for encrypt. When I click encryptButton, I want the return result of String encrypt(byte[]) to show in my Log. How do I achieve this ? What do I have to code in my activity ? Thanks in advance

para cuando en TRANSACT-SQL ?? :,v

Hi Guys,
function decrypt System.Security.Cryptography.RijndaelManaged and sample java above provide diff. value

Thanks in advance

Thank you @jafetsanchez ,
i use it to communicate between my Android App and Server written in VB.net (had to translate it first).