how to Encript and decript values

public  string Encrypt(string toEncrypt, bool useHashing)
    {
        byte[] keyArray;
        byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

        System.Configuration.AppSettingsReader settingsReader =
                                            new AppSettingsReader();
        // Get the key from config file

        string key = (string)settingsReader.GetValue("SiteName",
                                                         typeof(String));
        //System.Windows.Forms.MessageBox.Show(key);
        //If hashing use get hashcode regards to your key
        if (useHashing)
        {
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
            //Always release the resources and flush data
            // of the Cryptographic service provide. Best Practice

            hashmd5.Clear();
        }
        else
            keyArray = UTF8Encoding.UTF8.GetBytes(key);

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        //set the secret key for the tripleDES algorithm
        tdes.Key = keyArray;
        //mode of operation. there are other 4 modes.
        //We choose ECB(Electronic code Book)
        tdes.Mode = CipherMode.ECB;
        //padding mode(if any extra byte added)

        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform cTransform = tdes.CreateEncryptor();
        //transform the specified region of bytes array to resultArray
        byte[] resultArray =
          cTransform.TransformFinalBlock(toEncryptArray, 0,
          toEncryptArray.Length);
        //Release resources held by TripleDes Encryptor
        tdes.Clear();
        //Return the encrypted data into unreadable string format
        return Convert.ToBase64String(resultArray, 0, resultArray.Length);
    }

    public  string Decrypt(string cipherString, bool useHashing)
    {
        byte[] keyArray;
        //get the byte code of the string

        byte[] toEncryptArray = Convert.FromBase64String(cipherString);
        //byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(cipherString);

        System.Configuration.AppSettingsReader settingsReader =
                                            new AppSettingsReader();
        //Get your key from config file to open the lock!
        string key = (string)settingsReader.GetValue("SiteName",
                                                     typeof(String));

        if (useHashing)
        {
            //if hashing was used get the hash code with regards to your key
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
            //release any resource held by the MD5CryptoServiceProvider

            hashmd5.Clear();
        }
        else
        {
            //if hashing was not implemented get the byte code of the key
            keyArray = UTF8Encoding.UTF8.GetBytes(key);
        }

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        //set the secret key for the tripleDES algorithm
        tdes.Key = keyArray;
        //mode of operation. there are other 4 modes.
        //We choose ECB(Electronic code Book)

        tdes.Mode = CipherMode.ECB;
        //padding mode(if any extra byte added)
        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform cTransform = tdes.CreateDecryptor();
        byte[] resultArray = cTransform.TransformFinalBlock(
                             toEncryptArray, 0, toEncryptArray.Length);
        //Release resources held by TripleDes Encryptor               
        tdes.Clear();
        //return the Clear decrypted TEXT
        return UTF8Encoding.UTF8.GetString(resultArray);
    }