双语畅销书《艾伦图灵传》第5章:解谜接力赛(28)

It was an elegant method, but the disadvantage was that it depended entirely on the specific indicator system.

这是一场漂亮的胜利，但缺点是它完全依赖于这种特定的指示信号机制。

It did not last. The naval Enigma was the first to be lost, and6

然而这种机制并未一直存在，海军型谜机首先取消了这种机制：

… after the end of April 1937, when the Germans changed the naval indicators, they had been able to read the naval traffic only for the period from 30 April to8 May 1937, and that only retrospectively.

……1937年4月底，德国改变了海军的指示信号，于是他们只能解出4月30日到5月8日的海军通信，而且全是马后炮。

Moreover, this small success left them in no doubt that the new indicator system had given the Enigma machine a much higher degree of security…

这个变化使他们确信，新型指示信号大大提高了谜机的安全度……

And then on 15 September 1938, as Chamberlain flew to Munich, a greater disaster struck.

而在1938年9月15日，正当张伯伦飞往慕尼黑的时候，更大的灾难降临了，

All the other German systems were changed.

德国所有的通信系统都改换了指示信号。

It was only a minor modification, but it meant that overnight, all the catalogued cycle-lengths became completely worthless.

对德国来说，这只是一个小变化，但对波兰来说，这意味着所有的轮换长度档案，在一夜之间全部变成了废纸。

In the new system, the ground-setting was no longer fixed in advance.

在改进后的系统中，底层设定不再是事先固定好的，

Instead, it would be chosen by the cipher clerk, who therefore had to communicate it to the receiver.

而是由密码操作员来选择的。

This was done in the simplest possible way, by transmitting it as it stood.

然后，他就直接以明文的形式，把它发送给接收者。

Thus the clerk might choose AGH, then set the rotors to read AGH.

比如说，操作员选择AGH，那就把初始盘位设定为AGH，

He would then choose another setting, say TUI.

然后他会再选择一个盘位，比如TUI。

He would encipher TUITUI, to give say RYNFYP.

他会用AGH盘位来编码TUITUI，假如说得到了RYNFYP。

He would then transmit AGHRYNFYP as indicator letters, followed by the actual message as enciphered with the rotors starting on the setting TUI.

他将AGHRYNFYP发送出去，作为指示信号，然后开始发送用TUI盘位编码的信息正文。