Mã hóa MD5, Send Email, tạo password ngẫu nhiên

public string MD5(string password) // chuổi password cần mã hóa

    {

        byte[] textbytes = System.Text.Encoding.Default.GetBytes(password);

        try

        {

            System.Security.Cryptography.MD5CryptoServiceProvider crythandler;

            crythandler = new System.Security.Cryptography.MD5CryptoServiceProvider();

            byte[] hash = crythandler.ComputeHash(textbytes);

            String ret = "";

            foreach (byte a in hash)

            {

                if (a < 16)

                    ret += "0" + a.ToString("x");

                else

                    ret += a.ToString("x");

            }

            return ret;

        }

        catch

        {

            throw;

        }

    }

 /// hàm mã hóa password md5

        public string EncodePassword(string originalPassword)

        {

            //Declarations

            Byte[] originalBytes;

            Byte[] encodedBytes;

            MD5 md5;

            //Instantiate MD5CryptoServiceProvider, get bytes for original password and compute hash (encoded password)

            md5 = new MD5CryptoServiceProvider();

            originalBytes = UTF8Encoding.Default.GetBytes(originalPassword);

            encodedBytes = md5.ComputeHash(originalBytes);

            //Convert encoded bytes back to a 'readable' string

            return BitConverter.ToString(encodedBytes);

        }

public bool SendMailDetails(string Frommail, string pass, string Tomail, string Tenhienthi, string Title, string Content, string Host)

        {

            MailMessage mail = new MailMessage();

            mail.From = new MailAddress(Frommail, Tenhienthi, Encoding.UTF8);

            mail.To.Add(Tomail);

            mail.Subject = Title;

            mail.SubjectEncoding = Encoding.UTF8;

            mail.Body = Content;

            mail.BodyEncoding = System.Text.Encoding.UTF8;

            mail.IsBodyHtml = true;

            SmtpClient mySmtpClient = new SmtpClient();

            mySmtpClient.Host = Host;

            mySmtpClient.Credentials = new System.Net.NetworkCredential(Frommail, pass);

            mySmtpClient.EnableSsl = true;

            try { mySmtpClient.Send(mail); } //--Gửi mail

            catch { return false; }

            return true;

        }

       Host : smtp.gmail.com : nếu from mail là gmail

        // tạo ra password ngẫu nhiên

        public string GenerateRandomPassword(int length)

        {

            string allowedLetterChars = "abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

            string allowedNumberChars = "0123456789";

            char[] chars = new char[length];

            Random rd = new Random();

            bool useLetter = true;

            for (int i = 0; i < length; i++)

            {

                if (useLetter)

                {

                    chars[i] = allowedLetterChars[rd.Next(0, allowedLetterChars.Length)];

                    useLetter = false;

                }

                else

                {

                    chars[i] = allowedNumberChars[rd.Next(0, allowedNumberChars.Length)];

                    useLetter = true;

                }

            }

            return new string(chars);

        }