雙語暢銷書《艾倫圖靈傳》第5章:解謎接力賽(131)
... not by latitude and longitude.
Thus position AB1234 would indicate point, say 55 degrees 30 minutes North, 25 degrees 40 minutes West.
比如，AB1234可能代表着北緯55度30分，西經25度40分。This of course presented no problem to us once a portion of a gridded chart had been captured and the whole reconstructed.
這本身並無問題。
But in (September) 1941 the Germans started transposing these letters, square AB becoming, for example, XY
但是在1941年9月，德國人更換了這套標識，例如將AB換成XY，while a figure would have to be added to or subtracted from the numerals, so that 1234 would appear in the text of the signal as, say, 2345.
並且對數字進行了一些加減，例如1234在通信中會說成2345。These transpositions were changed at regular intervals.
這些變換本身，也按照某種規律，週期性地變化。Yet either the Enigma was being read, in which case these precautions were a feeble response, or it was not, in which case they were a waste of time.
如果說德國已經知道謎機被破解了，那麼這些改進措施就顯得太幼稚了，如果他們不知道，那麼這些措施就是浪費時間。The rationale lay not in foiling the British cryptanalysts, but in creating a defence against imagined spying and treachery.
但實際上，德國做出這些改變，並不是爲了難住英國的密碼專家，而是爲了防止可能會出現的間諜或叛變。The cumbersome disguise succeeded in confusing their own officers:
這些麻煩的變換，成功地迷惑了他們自己的官員：On one occasion we successfully solved a disguised grid reference and diverted a convoy clear of a waiting patrol line,
有一次，我們破解了一個座標網格，並在巡邏線上執行了一次護航清掃，only to find that the C.O. of one of the U-boats involved had not been as clever as we had and had misinterpreted the disguised grid reference given in his orders and blundered into the convoy in consequence.
結果只發現了一艘潛艇。這艘潛艇似乎誤解了他接到的命令中的座標，結果撞入了清掃範圍。In November 1941 the system was made even more complicated, and gave rise to long periods of uncertainty at Bletchley.
在1941年11月，這個系統被改得更加複雜，布萊切利陷入了長時間的困惑。They were still on a knife-edge, and were never allowed to forget it.
他們仍然站在刀尖上，從未忘記這一點。
