记住不要忘记命名空间的引用：

        using System.Security.Cryptography;
         
        public string PwdEncrypt(string pwd) // MD5加密密码.....

        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] data = System.Text.Encoding.Default.GetBytes(pwd);
            byte[] md5data = md5.ComputeHash(data);

            md5.Clear();
            string Str = "";
            for (int i = 0; i < md5data.Length - 1; i++)
            {
                Str += md5data[i].ToString("x").PadLeft(2, '0');
            }
            return Str;
        }

• 加密
• 算法