---
layout: post
title: IT9睇Steins;Gate – 回應中出羊子《IT人睇命運石之門的悲哀》
date: 2017-09-02 02:00:00 +0800
---
[羊子寫開][1]，我又寫吓，Steins;Gate 中唔合邏輯嘅嘢。Spoiler alert，未睇過Steins;Gate 嘅人，睇完先好睇呢篇文。

利申：未玩Steins;Gate 0（諗住等睇咗動畫先），呢度提出嘅嘢唔排除喺0入面已經解答咗。

## 36 bytes + metadata D-mail

Steins;Gate 入面，因為某啲原因，每次send D-mail 只可以send 到共36 bytes 內文，加埋普通e-mail 嘅metadata。但其實一個正常嘅e-mail，每次嘅metadata 長度都可以唔同（例如：sender/receiver e-mail address 長度唔同），咁點解e-mail 內文會有固定長度限制？而唔係metadata 少1 byte 內文可以send 多1 byte？

其次，其實metadata 係可以好長：

    Return-Path: <me@adrianiainlam.tk>
    Delivered-To: me@adrianiainlam.tk
    Received: from adrianiainlam.tk
    	by ibn5100 (Dovecot) with LMTP id vzEgG5eZqVliVAAAYrSuEQ
    	for <me@adrianiainlam.tk>; Sat, 02 Sep 2017 01:32:07 +0800
    Received: from localhost (localhost [127.0.0.1])
    	by adrianiainlam.tk (Postfix) with ESMTP id 5BB546C01119
    	for <me@adrianiainlam.tk>; Sat,  2 Sep 2017 01:32:07 +0800 (HKT)
    X-Virus-Scanned: Debian amavisd-new at adrianiainlam.tk
    Authentication-Results: adrianiainlam.tk (amavisd-new);
    	dkim=pass (1024-bit key) header.d=adrianiainlam.tk
    Received: from adrianiainlam.tk ([127.0.0.1])
    	by localhost (adrianiainlam.tk [127.0.0.1]) (amavisd-new, port 10024)
    	with ESMTP id Zhglg4P_20XC for <me@adrianiainlam.tk>;
    	Sat,  2 Sep 2017 01:32:06 +0800 (HKT)
    Received: from [223.16.86.123] (unknown [223.16.86.123])
    	(using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
    	(No client certificate requested)
    	(Authenticated sender: me@adrianiainlam.tk)
    	by adrianiainlam.tk (Postfix) with ESMTPSA id 7256A6C005E6
    	for <me@adrianiainlam.tk>; Sat,  2 Sep 2017 01:32:06 +0800 (HKT)
    DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=adrianiainlam.tk;
    	s=mail; t=1504287126;
    	bh=mV+Uarv6OWKOrBAKu7qk7/n4hFIO3UyDJqQiJD7YWAA=;
    	h=To:From:Subject:Date:From;
    	b=mp5lviODOsd23ViXB5korIInYAJKkjlptmh5WjsJ43ri/cViqEnpz3Z9W9DBAuFg7
    	 jLi/brhbRNgl0fGpSMTwcazzQUFDwSIqNkKFliCif7uusXKimQJkjNwP9oyJ4jakaV
    	 IQNwt3iuTA9EjXhy1xSYO/CwuGAoRyM9mUPcj9eE=
    To: me@adrianiainlam.tk
    From: Adrian I Lam <me@adrianiainlam.tk>
    Subject: Hey Mister
    Message-ID: <7711326e-2bfb-664e-0902-41543ec6d00e@adrianiainlam.tk>
    Date: Sat, 2 Sep 2017 01:32:05 +0800
    User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
     Thunderbird/52.2.1
    MIME-Version: 1.0
    Content-Type: text/plain; charset=utf-8
    Content-Transfer-Encoding: 7bit
    Content-Language: en-US

    I am mad scientist.
    It's so cool!
    Sonuvabitch.

以上e-mail 為例，真正內文只有最尾 "I am mad scientist" 去到 "Sonuvabitch" 三行，其餘全部都係metadata。既然send 到咁多嘢，點解（以Super hacker Daru 對電腦嘅認識）會冇人諗過運用metadata 再send 多啲嘢？例如：自己host 個postfix+dovecot，send 出時用個DKIM-Signature 裝多啲嘢，收e-mail 時再decode 返。（當然只適用於send 到發明電話微波爐（偽）之後時間）。

## 用黑洞壓縮information

呢點應該唔使我多講，compress information 係要用algorithm（要計數），compress matter 要用力。黑洞係唔識計數嘅，只係有好大力啫。

## Time leap 到發明Time leap machine 之前

呢點喺第一點亦略有帶過，即使假設佢哋有方法將兩日嘅記憶壓縮到36 bytes，請問佢哋解壓器喺邊？佢哋最多只可以喺發明Time leap machine 之後（或其間）先設計解壓器，亦即係話發明Time leap machine 之前，鳳凰院凶真部手機係冇可能將佢嘅記憶解壓，亦即係冇可能time leap 到發明Time leap machine 之前。

## 結論

睇Steins;Gate，唔係睇佢點樣**發明**部時光機，而係睇佢點樣**用**部時光機。

[1]: https://www.facebook.com/photo.php?fbid=119131008820676&set=a.116277805772663.1073741829.100021713331172&type=3&theater