服了酷到让人望而生畏密码学能解释得如此简单图解密码技术( 五 ) _为什么上淘宝要密码

英语中出现频率较高的字母中，只有o 还没有出现在我们的假设中。相对地，密文中出现频率较高的字母中，还没有找到对应关系的有G 和Z 。我们先假设G → o 。
使用上面所有的假设重新替换一下密文。

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噢噢，这回在末尾出现了Cannotget 这样的组合，那么C → c 应该是没错了。既然C → c，那么刚才我们的假设N → c 就是错误的了。
Shich 这个组合，大概是which 吧（S → w）。
除了高频字母以外，密文中的低频字母Q 也可以找到一些相关的组合。
例如thethingtoQRench 这个组合，应该是the thing to QRench 。查字典发现有quench 这样一个单词（Q → q，R → u）。quench 是“解渴”的意思，大概文章讲的是关于喝水的话题吧。
接下来会发现hotZuUUer 这个组合，大概是hot summer 吧（Z → s，U → m）。U 连续出现了两次，这是一个关键性的线索，而且和“解渴”的上下文也比较符合。
successagainanAagain 很明显应该是success again and again（A → d）。
triedaLter 应该是tried after（L → f）。
whatXoucannotget 应该是what you cannot get（X → y）。
thefoVandthegraNesonehotsummersday 应该是the fox and the grapes one hot summers day（V → x，N → p）。
用上面的假设重新替换密文后，我们发现小写字母的比例大幅增加，这说明我们已经基本上完成了破译工作。
thefoxandthegrapesonehotsummersdayafoxwasstroKKingthroughanorchardtiKKhecametoaFunchofgrapesHustripeningonaTinewhichhadFeentrainedoTeraKoftyFranchHustthethingtoquenchmythirstquothhedrawingFacJafewpaceshetooJarunandaHumpandHustmissedtheFunchturningroundagainwithaonetwothreeheHumpedupFutwithnogreatersuccessagainandagainhetriedafterthetemptingmorseKFutatKasthadtogiTeitupandwaKJedawaywithhisnoseintheairsayingiamsuretheyaresouritiseasytodespisewhatyoucannotget
接下来我们再列举一些线索。
foxwasstroKKing
fox was strolling
(K → l)
hetooJarunandaHumpandHustmissed
he took a run and a jump and just missed
(H → j)
(J → k)
hejumpedupFutwithnogreatersuccess
he jumped up but with no greater success
(F → b)
butatlasthadtogiTeitup
but at last had to give it up
(T → v)
没有使用到的最后一个字母
(B → z)
这样我们就全部破译出来了！密钥（替换表）如下。

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明文如下。
thefoxandthegrapesonehotsummersdayafoxwasstrollingthroughanorchardtillhecametoabunchofgrapesjustripeningonavinewhichhadbeentrainedoveraloftybranchjustthethingtoquenchmythirstquothhedrawingbackafewpaceshetookarunandajumpandjustmissedthebunchturningroundagainwithaonetwothreehejumpedupbutwithnogreatersuccessagainandagainhetriedafterthetemptingmorselbutatlasthadtogiveitupandwalkedawaywithhisnoseintheairsayingiamsuretheyaresouritiseasytodespisewhatyoucannotget
补上空格和标点符号之后，文章就变得非常易读了。
"The Fox and the Grapes"
One hot summer's day, a Fox was strolling through an orchard till he came to a bunch of grapes just ripening on a vine which had been trained over a lofty branch. "Just the thing to quench my thirst," quoth he. Drawing back a few paces, he took a run and a jump, and just missed the bunch. Turning round again with a one, two, three, he jumped up, but with no greater success. Again and again he tried after the tempting morsel, but at last had to give it up,and walked away with his nose in the air, saying: "I am sure they are sour."
It is easy to despise what you cannot get.
原来这段文章就是《伊索寓言》中《狐狸和葡萄》的故事。
通过上面的破解过程，我们可以总结出下列结论。