That was what old Comrade Chen was good at. Thanks to his understanding of the way enemy intelligence operations worked, and the vast and swelling sea of information he had accumulated over the years, he could build something out of nothing. It was as if a writer were such a genius that he could write a whole book without knowing anything about grammar. Twenty years earlier, before cryptography was computerized in other countries, being able to read a message in its entirety was priceless, because it could set in motion a domino effect whereby the whole cipher would be laid bare.

We then held another meeting, to discuss how to proceed in the light of Comrade Chen’s reading of this secret message. It seemed that Huang Yiyi didn’t think much of Chen’s achievements, because at the meeting she said, ‘First of all I would like to congratulate Comrade Chen on his little breakthrough; for the first time we can read an entire radio message. That means that we can now be sure that we are on the right track. But Comrade Chen seems to be under the impression that this has been a massive advance for our cryptographic work and determines the next steps in the process, and I am afraid I don’t agree with him. In my opinion this is a very simple message and will be of no help at all in our work on cracking RECOVERY. This is just a single hair when we are dealing with nine head of oxen. While from the presence of the ox’s hair we can be sure of the existence of the oxen, we mustn’t be too optimistic, nor should we make a hasty decision that sends our decryption down the wrong route.’

Comrade Chen retorted, ‘What do you mean, a hair? In the past we often found the whole ox by starting from a couple of hairs.’

‘That was in the past. At that point ciphers relied on human encryption skills, so that one message could lead you on to the next, and then to the third and fourth. Modern ciphers are mathematical problems, and if you want to solve them you have to work out the equations on which they are based, how they are formulated and how they develop. Otherwise one is one and two is two, and you can’t hope to get one and then have the rest fall into your lap. You must not be under any illusions about that.’

Chen glared at her and asked her to come up with something better instead. She waved her hands and said that she had nothing to suggest.