雙語暢銷書《艾倫圖靈傳》第5章:解謎接力賽(28)
It was an elegant method, but the disadvantage was that it depended entirely on the specific indicator system.
It did not last. The naval Enigma was the first to be lost, and6
然而這種機制並未一直存在，海軍型謎機首先取消了這種機制：… 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，德國改變了海軍的指示信號，於是他們只能解出4月30日到5月8日的海軍通信，而且全是馬後炮。
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…
這個變化使他們確信，新型指示信號大大提高了謎機的安全度……And then on 15 September 1938, as Chamberlain flew to Munich, a greater disaster struck.
而在1938年9月15日，正當張伯倫飛往慕尼黑的時候，更大的災難降臨了，All the other German systems were changed.
德國所有的通信系統都改換了指示信號。It was only a minor modification, but it meant that overnight, all the catalogued cycle-lengths became completely worthless.
對德國來說，這只是一個小變化，但對波蘭來說，這意味着所有的輪換長度檔案，在一夜之間全部變成了廢紙。In the new system, the ground-setting was no longer fixed in advance.
在改進後的系統中，底層設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.
而是由密碼操作員來選擇的。This was done in the simplest possible way, by transmitting it as it stood.
然後，他就直接以明文的形式，把它發送給接收者。Thus the clerk might choose AGH, then set the rotors to read AGH.
比如說，操作員選擇AGH，那就把初始盤位設定爲AGH，He would then choose another setting, say TUI.
然後他會再選擇一個盤位，比如TUI。He would encipher TUITUI, to give say RYNFYP.
他會用AGH盤位來編碼TUITUI，假如說得到了RYNFYP。He would then transmit AGHRYNFYP as indicator letters, followed by the actual message as enciphered with the rotors starting on the setting TUI.
他將AGHRYNFYP發送出去，作爲指示信號，然後開始發送用TUI盤位編碼的信息正文。
