c# 加密类 示例代码

【核心代码】

 #region 公共函数 静态成员 提供字符串MD5加密功能
        // MD5加密，通常用在用户密码的加密和验证 ,暂时不可用
        public static string MD5_Encrypt(string val)
        {
            string EncryptPassword = "";
            //EncryptPassword = FormsAuthentication.HashPasswordForStoringInConfigFile(val, "MD5");
            return EncryptPassword;
        }
        #endregion

        #region 公共函数 静态成员 提供字符串DES加密功能
        // DES加密
        public static string DES_Encrypt(string val)
        {
            string Code = "";
            if (!val.Equals(""))
            {
                DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, cryptoProvider.CreateEncryptor(Key_64, Iv_64), CryptoStreamMode.Write);
                StreamWriter sw = new StreamWriter(cs);
                sw.Write(val);
                sw.Flush();
                cs.FlushFinalBlock();
                ms.Flush();
                int Length = (int)ms.Length;

                Code = Convert.ToBase64String(ms.GetBuffer(), 0, Length);
            }
            return Code;
        }
        #endregion

        #region 公共函数 静态成员 提供字符串DES解密功能
        // DES解密
        public static string DES_Decrypt(string val)
        {
            string Code = "";
            if (!val.Equals(""))
            {
                DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
                byte[] buffer = Convert.FromBase64String(val);
                MemoryStream ms = new MemoryStream(buffer);
                CryptoStream cs = new CryptoStream(ms, cryptoProvider.CreateDecryptor(Key_64, Iv_64), CryptoStreamMode.Read);
                StreamReader sr = new StreamReader(cs);
                Code = sr.ReadToEnd();
            }
            return Code;
        }
        #endregion

        #region 线性加密
        #region 私有函数 整型 尾列加密
        private static int Sha_End(int val)
        {

            return T1[val];
        }
        #endregion

        #region 私有函数 整型 尾列解密
        private static int Sha_GetEnd(int val)
        {
            return T2[val];
        }
        #endregion

        #region 私有函数 整型 单步卷帘加密
        private static int Sha_Next(int val, int pre, bool flag)
        {
            int result = flag ? ((val   KeyArray1[pre]) % 10) : ((val   KeyArray2[pre]) % 10);
            return (result   1) % 10;
        }
        #endregion

        #region 私有函数 整型 单步卷帘解密
        private static int Sha_Next2(int val, int pre, bool flag)
        {
            int result;
            val = (val   9) % 10;
            if (flag)
            {
                val = val >= KeyArray1[pre] ? val : val   10;
                result = val - KeyArray1[pre];
            }
            else
            {
                val = val >= KeyArray2[pre] ? val : val   10;
                result = val - KeyArray2[pre];
            }
            return result;

        }
        #endregion

        #region 公有方法 整型 全数卷帘加密
        public static string Line_Encrypt(int intval)
        {
            return Line_Encrypt((long)intval);
        }
        public static string Line_Encrypt(long intval)
        {
            string val = intval.ToString();
            int i;
            string temp = "";
            bool flag = true;
            int temp2, temp3, temp4;
            //先求出最后一后数
            int pre = Sha_End(Convert.ToInt32(val.Substring(val.Length - 1, 1)));
            //从倒数第二位开始
            temp4 = pre;
            for (i = val.Length - 2; i >= 0; i--)
            {
                //取出该位数字
                temp3 = Convert.ToInt32(val.Substring(i, 1));
                //算出加密码,即倒数第二位加密后放在第一位。
                temp2 = Sha_Next(temp3, pre, flag);
                temp  = temp2;
                pre = temp2;
                flag = !flag;
            }
            return temp   temp4;
        }
        #endregion

        #region 公有方法 整型 全数卷帘解密
        public static string Line_Decrypt(int intval)
        {
            string val = intval.ToString();
            int i;
            string temp = "";
            bool flag = true;
            int temp2, temp3, temp4;

            //先求出最后一后数
            int pre = Convert.ToInt32(val.Substring(val.Length - 1, 1));
            //从倒数第二位开始
            temp4 = Sha_GetEnd(pre);
            for (i = 0; i < val.Length - 1; i  )
            {
                //取出该位数字
                temp3 = Convert.ToInt32(val.Substring(i, 1));
                //算出加密码,即倒数第二位加密后放在第一位。

                temp2 = Sha_Next2(temp3, pre, flag);
                temp = temp2   temp;
                pre = temp3;
                flag = !flag;
            }
            return temp   temp4;
        }
        #endregion
        #endregion

        #endregion // By Simon

        #region MD5, 3DES encrypt and decrypt methods
        /// <summary>
        /// MD5加密方法
        /// </summary>
        /// <param name="a_strValue">string to be encrypted</param>
        /// <returns>encrypted string</returns>
        public static string EncryptMD5String(string a_strValue)
        {
            try
            {
                //change to bytearray
                Byte[] hba = ((HashAlgorithm)CryptoConfig.CreateFromName("MD5")).
                 ComputeHash(StringToByteArray(a_strValue));

                return ByteArrayToString(hba);
            }
            catch (Exception ex)
            {
                throw (ex);
            }
        }