This was Malcolm MacPhail, a Canadian physicist, who became involved in a sideline that Alan took up.
这就是麦卡姆·麦克菲尔，他参与了艾伦的一项副业：
It was probably in the fall of 1937 that Turing first became alarmed about a possible war with Germany.
大概是在1937年的秋天，图灵首先警觉，德国可能会引发一场战争。
He was at that time supposedly working hard on his famous thesis but nevertheless found time to take up the subject of cryptanalysis with characteristic vigour.
那时，他除了埋头工作于他著名的论文之外，还发挥他的智力，抽时间研究密码学。
…on this topic we had many discussions.
在这方面，我们讨论了很多。
He assumed that words would be replaced by numbers taken from an official code book and messages would be transmitted as numbers in the binary scale.
他想到，通过一个约定的密码手册，可以把单词转化成数，这样就可以把一条信息转化成一串二进制数。
But, to prevent the enemy from deciphering captured messages even if they had the code book, he would multiply the number corresponding to a specific message by a horrendously long but secret number and transmit the product.
为了让敌人即使掌握了密码手册也不能破解信息，就要把这个代表特定信息的数，乘以一个非常大的密钥数，然后传输它们的乘积。
The length of the secret number was to be determined by the requirement that it should take 100 Germans working eight hours a day on desk calculators 100 years to discover the secret factor by routine search!
这个密钥数的长度，可以根据需要来设定，应该保证在一个德国人每天用台式计算器工作8小时的情况下，需要花费100年才能算出这个密钥。
Turing actually designed an electric multiplier and built the first three or four stages to see if it could be made to work.
实际上，图灵还设计了一个电动乘法机，并且制造了前三个或四个模块，来试验它是否能工作。
For the purpose he needed relay-operated switches which, not being commercially available at that time, he built himself.
为了实现这个计划，他需要一种继电器开关，当时在市场上买不到，于是他要自己制作。