Asp.net 加密解密类

namespace Wedn.Net
{
    /// <summary> 
    /// EncryptHelper 来′自? wedn.net 
    /// </summary> 
    public class EncryptHelper
    {
        // 提á供?8个?字?符?作÷为aDES密ü钥?（¨程ì序ò自?动ˉ截?取?前°8个?字?符?）? 
        private static string key = "iceStone";

        /// <summary>
        /// DES对?称?加ó密ü解a密ü的?密ü钥?
        /// </summary> 
        public static string Key
        {
            get
            {
                return key;
            }
            set
            {
                key = value;
            }
        }

        /// <summary>
        /// MD5 加ó密ü（¨不?可é逆?加ó密ü）?
        /// </summary>
        /// <param name="pass">要a加ó密ü的?原-始?字?串?</param>
        /// <returns></returns> 
        public static string MD5Encrypt(string pass)
        {
            System.Security.Cryptography.MD5 md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] bytResult = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
            md5.Clear();
            string strResult = BitConverter.ToString(bytResult);
            strResult = strResult.Replace("-", "");
            return strResult;
            /* 另í一?种?方?法¨
            pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "MD5");
            return pass;
            */
        }

        /// <summary>
        /// SHA1 加ó密ü（¨不?可é逆?加ó密ü）?
        /// </summary>
        /// <param name="pass">要a加ó密ü的?原-始?字?串?</param>
        /// <returns></returns> 
        public static string SHA1Encrypt(string pass)
        {
            System.Security.Cryptography.SHA1 sha1 = new System.Security.Cryptography.SHA1CryptoServiceProvider();
            byte[] bytResult = sha1.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
            sha1.Clear();
            string strResult = BitConverter.ToString(bytResult);
            strResult = strResult.Replace("-", "");
            return strResult;
            /* 另í一?种?方?法¨
            pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "SHA1");
            return pass;
            */
        }

        /// <summary>
        /// DES加ó密ü字?符?串?
        /// </summary>
        /// <param name="encryptString">待y加ó密ü的?字?符?串?</param>
        /// <returns>加ó密ü成é功|返μ回?加ó密ü后ó的?字?符?串?，?失§败ü返μ回?源′串?</returns> 
        public static string DESEncrypt(string encryptString)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] rgbIV = rgbKey;
                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();
                cStream.Close();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解a密ü字?符?串?
        /// </summary>
        /// <param name="decryptString">待y解a密ü的?字?符?串?</param>
        /// <returns>解a密ü成é功|返μ回?解a密ü后ó的?字?符?串?，?失§败ü返μ源′串?</returns> 
        public static string DESDecrypt(string decryptString)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] rgbIV = rgbKey;
                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();
                cStream.Close();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }

        /// <summary>
        /// 将?普?通¨字?符?串?编à码?为aBASE64字?串?
        /// </summary>
        /// <param name="str">源′字?符?串?</param>
        /// <returns></returns> 
        public static string Base64Encode(string str)
        {
            return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
        }

        /// <summary>
        /// 解a码?BASE64字?串?
        /// </summary>
        /// <param name="str">Base64字?串?</param>
        /// <returns></returns> 
        public static string Base64Decode(string base64Str)
        {
            return Encoding.UTF8.GetString(Convert.FromBase64String(base64Str));
        }
    }
}