（原创）常用加密解密

加密

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

        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();

        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));

        if (useHashing)
        {
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));

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

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

        tdes.Key = keyArray;

        tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform cTransform = tdes.CreateEncryptor();

        byte[] resultArray = cTransform.TransformFinalBlock
                (toEncryptArray, 0, toEncryptArray.Length);
        tdes.Clear();
        return Convert.ToBase64String(resultArray, 0, resultArray.Length);
    }

解密：

public static string Decrypt(string cipherString, bool useHashing)
    {
        byte[] keyArray;


        byte[] toEncryptArray = Convert.FromBase64String(cipherString);

        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));

        if (useHashing)
        {
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));

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

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

        tdes.Key = keyArray;
        

        tdes.Mode = CipherMode.ECB;

        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform cTransform = tdes.CreateDecryptor();
        byte[] resultArray = cTransform.TransformFinalBlock
                (toEncryptArray, 0, toEncryptArray.Length);

        tdes.Clear();

        return UTF8Encoding.UTF8.GetString(resultArray);
    }