.NET（C#）代碼加密

public class Security
{
    string _QueryStringKey = "asdfghjk"; //URL傳輸參數加密Key,8個字元
    string _PassWordKey = "abcabcab";　//PassWord加密Key

    public Security()
    {
        //
        // TODO: 在此處添加建構函式邏輯 //
    }

    /// <summary>
    /// 加密URL傳輸的字串
    /// </summary>
    /// <param name="QueryString"></param>
    /// <returns></returns>
    public string EncryptQueryString(string QueryString)
    {
        return Encrypt(QueryString, _QueryStringKey);
    }

    /// <summary>
    /// 解密URL傳輸的字串
    /// </summary>
    /// <param name="QueryString"></param>
    /// <returns></returns>
    public string DecryptQueryString(string QueryString)
    {
        return Decrypt(QueryString, _QueryStringKey);
    }

   /// <summary>
    /// 加密帳號口令
   /// </summary>
   /// <param name="PassWord"></param>
   /// <returns></returns>
    public string EncryptPassWord(string PassWord)
    {
        return Encrypt(PassWord, _PassWordKey);
    }

   /// <summary>
    ///  解密帳號口令
   /// </summary>
   /// <param name="PassWord"></param>
   /// <returns></returns>
    public string DecryptPassWord(string PassWord)
    {
        return Decrypt(PassWord, _PassWordKey);
    }

    /// <summary>
    /// DEC 加密過程
    /// </summary>
    /// <param name="pToEncrypt"></param>
    /// <param name="sKey"></param>
    /// <returns></returns>
    public string Encrypt(string pToEncrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();　//把字串放到byte數組中

        byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
        //byte[]　inputByteArray=Encoding.Unicode.GetBytes(pToEncrypt);

        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密對象的密鑰和位移量
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法
        MemoryStream ms = new MemoryStream();　　 //使得輸入密碼必須輸入英文文本
        CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

        cs.Write(inputByteArray, 0, inputByteArray.Length);
        cs.FlushFinalBlock();

        StringBuilder ret = new StringBuilder();
        foreach (byte b in ms.ToArray())
        {
            ret.AppendFormat("{0:X2}", b);
        }
        ret.ToString();
        return ret.ToString();
    }

    /// <summary>
    /// DEC 解密過程
    /// </summary>
    /// <param name="pToDecrypt"></param>
    /// <param name="sKey"></param>
    /// <returns></returns>
    public string Decrypt(string pToDecrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();

        byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
        for (int x = 0; x < pToDecrypt.Length / 2; x++)
        {
            int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
            inputByteArray[x] = (byte)i;
        }

        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密對象的密鑰和位移量，此值重要，不能修改
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
        MemoryStream ms = new MemoryStream();
        CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

        cs.Write(inputByteArray, 0, inputByteArray.Length);
        cs.FlushFinalBlock();

        StringBuilder ret = new StringBuilder();　//建立StringBuild對象，CreateDecrypt使用的是流對象，必須把解密後的文本變成流對象

        return System.Text.Encoding.Default.GetString(ms.ToArray());
    }

    /// <summary>
    ///  檢查己加密的字串是否與原文相同
    /// </summary>
    /// <param name="EnString"></param>
    /// <param name="FoString"></param>
    /// <param name="Mode"></param>
    /// <returns></returns>
    public bool ValidateString(string EnString, string FoString, int Mode)
    {
        switch (Mode)
        {
            default:
            case 1:
                if (Decrypt(EnString, _QueryStringKey) == FoString.ToString())
                {
                    return true;
                }
                else
                {
                    return false;
                }
            case 2:
                if (Decrypt(EnString, _PassWordKey) == FoString.ToString())
                {
                    return true;
                }
                else
                {
                    return false;
                }
        }
    }
}