I'm sharing my Rijndael's encryptor/decryptor helper classes for C# and Java.
P.S. This is a first draft, but you can always refactor to improve, if you do it, don't forget to share it with la banda.
For .NET (RijndaelCrypt.cs) which I use to encrypt my JSON response in a RESTful Web Service I wrote in WCF.
#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 } }
For Java (RijndaelCrypt.java) which I use on my Android client to decrypt the response from the Web Service mentioned above.
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; } } }
Download from GitHub
Enjoy
