雙語暢銷書《艾倫圖靈傳》第5章:解謎接力賽(7)

One way of doing this was by means of the one-time principle.

其中一個重要的原則，叫作一次性原則。

This was one of the few sound ideas of 1930s cryptography, as well as the simplest.

對於30年代的密碼技術來說，這是一個簡單又實用的方法。

It required the key to be written out explicitly, twice over, and one copy given to the sender, one to the receiver of the transmission.

把密鑰複製兩份，一份給信息的發送方，另一份給接收方。

The argument for the security of this system was that provided the key were constructed by some genuinely completely random process, such as shuffling cards or throwing dice, there could be nothing for the enemy cryptanalyst to go on.

該系統的安全性就在於，只要密碼是完全隨機生成的，那麼敵人的密碼分析員就束手無策。

Given cipher text '5673', for instance, the analyst might guess that the plain-text was in fact '6743' and the key therefore '9930', or might guess that the plaintext was '8442' and the key '7231', but there would be no way of verifying such a guess, nor reason to prefer one guess to another.

比如，給出一個密文"5673"，分析員可能會猜，明文是"6743"而密鑰是"9930"，但是，也有可能明文是"8442"而密鑰是"7231"，他無法判斷哪種猜想是正確的，也看不出來哪一種更像是正確的。

The argument depended upon the key being absolutely patternless, and spread evenly over the possible digits, for otherwise the analyst would have reason to prefer one guess to another.

因爲密鑰是沒有規律的，每個數字都有均等的概率。

Indeed, discerning a pattern in the apparently patternless was essentially the work of the cryptanalyst, as of the scientist.

實際上，在明顯無規律的密碼中找到內在的規律，這就是科學家和密碼分析員的工作。

In the British system, one-time pads were produced, to be used up one at a time.

在英國通信系統中，有一次性的密鑰本，每次使用一頁，

Provided the key was random, no page was used twice, and the pads were never compromised, the system was fool-proof.

取出一組隨機的密鑰，用過了就作廢。每一頁的密鑰都是不同的，因此這個系統十分安全。

But it would involve the manufacture of a colossal quantity of key, equal in volume to the maximum that the particular communication link might require.

但是，這需要人工編制大量的密鑰，從工作量來說，甚至與通信本身不相上下。

Presumably this thankless task was undertaken by the ladies of the Construction Section of GC and CS, which on the outbreak of war was evacuated not to Bletchley but to Mansfield College, Oxford.

這項吃力又枯燥的工作，由政密學校編構部門的女士們來承擔，該部門在戰爭爆發後，並沒有撤入布萊切利莊園，而是遷到了牛津大學曼斯菲爾德學院。

As for the system in use, that was no joy either. Malcolm Muggeridge, who was employed in the secret service, found it2

至於使用的系統，也沒什麼樂趣.。情報部門的麥卡姆·馬格瑞治說：