Error in Encryption and Decryption

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Hi,

I m using the code to decrypt some details and again encrypt it to view the original, but some details are got double encrypted and I am not able to decrypt the details. Please help.

The code i m using is

public static string EncryptData(string Message)
    {
        byte[] Results;
        System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();
        MD5CryptoServiceProvider HashProvider = new MD5CryptoServiceProvider();
        byte[] TDESKey = HashProvider.ComputeHash(UTF8.GetBytes(passphrase));
        TripleDESCryptoServiceProvider TDESAlgorithm = new TripleDESCryptoServiceProvider();
        TDESAlgorithm.Key = TDESKey;
        TDESAlgorithm.Mode = CipherMode.ECB;
        TDESAlgorithm.Padding = PaddingMode.PKCS7;
        byte[] DataToEncrypt = UTF8.GetBytes(Message);
        try
        {
            ICryptoTransform Encryptor = TDESAlgorithm.CreateEncryptor();
            Results = Encryptor.TransformFinalBlock(DataToEncrypt, 0, DataToEncrypt.Length);
        }
        finally
        {
            TDESAlgorithm.Clear();
            HashProvider.Clear();
        }
        return Convert.ToBase64String(Results);
    }


public static string DecryptString(string Message)
    {
        byte[] Results;
        System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();
        MD5CryptoServiceProvider HashProvider = new MD5CryptoServiceProvider();
        byte[] TDESKey = HashProvider.ComputeHash(UTF8.GetBytes(passphrase));
        TripleDESCryptoServiceProvider TDESAlgorithm = new TripleDESCryptoServiceProvider();
        TDESAlgorithm.Key = TDESKey;
        TDESAlgorithm.Mode = CipherMode.ECB;
        TDESAlgorithm.Padding = PaddingMode.PKCS7;
        byte[] DataToDecrypt = Convert.FromBase64String(Message);
        try
        {
            ICryptoTransform Decryptor = TDESAlgorithm.CreateDecryptor();
            Results = Decryptor.TransformFinalBlock(DataToDecrypt, 0, DataToDecrypt.Length);
        }
        finally
        {
            TDESAlgorithm.Clear();
            HashProvider.Clear();
        }
        return UTF8.GetString(Results);
    }

I m geting the below error

Invalid length for a Base-64 char array.

Posted 27-Jun-13 1:03am

Rahul Jain1

Updated 27-Jun-13 1:19am

Rajesh Anuhya

v2

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Rajesh Anuhya · Answer 1 · 2013-06-27T01:22:00

Solution 1

I think you forget to convert the string from base64 to normal string while decrypting

use this

Convert.FromBase64String(

in

DecryptString(

method

Thanks
--RA

Posted 27-Jun-13 1:22am

Rajesh Anuhya

Comments

ArunRajendra 27-Jun-13 7:31am

I have tried the orginal code posted by "Rahul Jain1" it works with the reported conversion.

Sadique KT · Answer 2 · 2013-06-27T01:24:00

Here is one method..just try..

C#

private static string Encrypt(string plainStr, string completeEncodedKey, int keySize)
    {
        RijndaelManaged aesEncryption = new RijndaelManaged();
        aesEncryption.KeySize = keySize;
        aesEncryption.BlockSize = 128;
        aesEncryption.Mode = CipherMode.CBC;
        aesEncryption.Padding = PaddingMode.PKCS7;
        aesEncryption.IV = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[0]);
        aesEncryption.Key = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[1]);
        byte[] plainText = Encoding.UTF8.GetBytes(plainStr);
        ICryptoTransform crypto = aesEncryption.CreateEncryptor();
        // The result of the encryption and decryption
        byte[] cipherText = crypto.TransformFinalBlock(plainText, 0, plainText.Length);
        return Convert.ToBase64String(cipherText);
    }




    private static string Decrypt(string encryptedText, string completeEncodedKey, int keySize)
    {
        RijndaelManaged aesEncryption = new RijndaelManaged();
        aesEncryption.KeySize = keySize;
        aesEncryption.BlockSize = 128;
        aesEncryption.Mode = CipherMode.CBC;
        aesEncryption.Padding = PaddingMode.PKCS7;
        aesEncryption.IV = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[0]);
        aesEncryption.Key = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[1]);
        ICryptoTransform decrypto = aesEncryption.CreateDecryptor();
        byte[] encryptedBytes = Convert.FromBase64CharArray(encryptedText.ToCharArray(), 0, encryptedText.Length);
        return Encoding.UTF8.GetString(decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length));
    }