C# MD5加密

public static string Encrypt(string txt)
        {
            System.Security.Cryptography.MD5CryptoServiceProvider md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] bytes = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(txt));

            return BitConverter.ToString(bytes).Replace("-", "");
        }

        public static string Encrypt2(string txt)
        {
            System.Security.Cryptography.MD5CryptoServiceProvider md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] bytes = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(txt));
            StringBuilder sb = new StringBuilder();
            foreach(byte b in bytes)
            {
                sb.Append(b.ToString("X").PadLeft(,''));
            }
            return sb.ToString();
        }