.net md5

 public string GetMd5(string user)
    {
        using (MD5 md5 = MD5.Create())
        {
            byte[] msgbyte = Encoding.Default.GetBytes(user);
            byte[] md5byte = md5.ComputeHash(msgbyte);
            md5.Clear();
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < md5byte.Length; i++)
            {
                sb.Append(md5byte[i].ToString("x2"));
            }
            return sb.ToString();

        }
    }