MD5Util

    public class MD5Util
    {
        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="encypStr">加密字符串</param>
        /// <param name="charset">编码方式</param>
        /// <returns></returns>
        public static string GetMD5(string encypStr, string charset)
        {
            string retStr;
            MD5CryptoServiceProvider m5 = new MD5CryptoServiceProvider();

            //创建md5对象
            byte[] inputBye;
            byte[] outputBye;

            //使用GB2312编码方式把字符串转化为字节数组．
            try
            {
                inputBye = Encoding.GetEncoding(charset).GetBytes(encypStr);
            }
            catch (Exception ex)
            {
                inputBye = Encoding.GetEncoding("GB2312").GetBytes(encypStr);
            }
            outputBye = m5.ComputeHash(inputBye);

            retStr = System.BitConverter.ToString(outputBye);
            retStr = retStr.Replace("-", "").ToUpper();
            return retStr;
        }

        /// <summary>
        /// 对字符串进行SHA1加密
        /// </summary>
        /// <param name="strIN">需要加密的字符串</param>
        /// <returns>密文</returns>
        public static string SHA1_Encrypt(string Source_String)
        {
            byte[] StrRes = Encoding.Default.GetBytes(Source_String);
            HashAlgorithm iSHA = new SHA1CryptoServiceProvider();
            StrRes = iSHA.ComputeHash(StrRes);
            StringBuilder EnText = new StringBuilder();
            foreach (byte iByte in StrRes)
            {
                EnText.AppendFormat("{0:x2}", iByte);
            }
            return EnText.ToString();
        }

        /// <summary>
        /// SHA256加密，不可逆转
        /// </summary>
        /// <param name="str">string str:被加密的字符串</param>
        /// <returns>返回加密后的字符串</returns>
        private static string SHA256Encrypt(string str)
        {
            System.Security.Cryptography.SHA256 s256 = new System.Security.Cryptography.SHA256Managed();
            byte[] byte1;
            byte1 = s256.ComputeHash(Encoding.Default.GetBytes(str));
            s256.Clear();
            return Convert.ToBase64String(byte1);
        }

        /// <summary>
        /// SHA384加密，不可逆转
        /// </summary>
        /// <param name="str">string str:被加密的字符串</param>
        /// <returns>返回加密后的字符串</returns>
        private static string SHA384Encrypt(string str)
        {
            System.Security.Cryptography.SHA384 s384 = new System.Security.Cryptography.SHA384Managed();
            byte[] byte1;
            byte1 = s384.ComputeHash(Encoding.Default.GetBytes(str));
            s384.Clear();
            return Convert.ToBase64String(byte1);
        }


        /// <summary>
        /// SHA512加密，不可逆转
        /// </summary>
        /// <param name="str">string str:被加密的字符串</param>
        /// <returns>返回加密后的字符串</returns>
        private static string SHA512Encrypt(string str)
        {
            System.Security.Cryptography.SHA512 s512 = new System.Security.Cryptography.SHA512Managed();
            byte[] byte1;
            byte1 = s512.ComputeHash(Encoding.Default.GetBytes(str));
            s512.Clear();
            return Convert.ToBase64String(byte1);
        }

        //默认密钥向量
        private static byte[] Keys = { 0xEF, 0xAB, 0x56, 0x78, 0x90, 0x34, 0xCD, 0x12 };
        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <param name="encryptKey">加密密钥,要求为8位</param>
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
        public static string EncryptDES(string encryptString, string encryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
        public static string DecryptDES(string decryptString, string decryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }
    }