The report was very long, and the data therein both complex and abstruse, and so it was very slow reading for me. But Huang Yiyi finished it quickly and came rushing in to find me. When she saw I was still reading through the report she said angrily, ‘Don’t look! Don’t look! There is nothing to read. Sivincy is a cow!’

I told her to sit down and explain what she meant, and at the same time I got Comrade Fei to call Chen in to hear what she had to say. She was almost bouncing up and down in her chair, desperate to speak. I told her to wait until Chen arrived. She didn’t pay any attention, but started in: ‘It’s a scandal, that’s what it is. I am quite sure now that the reason the Americans didn’t use DIFFICULT CENTURY themselves but gave it to the Taiwanese was because they found out what a nasty trick Sivincy had pulled, and started to have their doubts about her character. If people start worrying about the character of the person writing ciphers for them, is it likely they’re going to use them? Particularly not when she has Soviet bones under her nice new American skin!’

What she said confused both me and Comrade Chen, who had arrived in the middle of it all, and we just looked at her blankly.

‘What I want to say is very simple,’ she explained. ‘Both of you have worked in cryptography for so long that I’m sure you’re well aware that during the Second World War the Germans used a famous cipher called ULTRA.’

‘The Enigma machine,’ I said.

‘Yes, Enigma.’

‘Enigma I know about,’ Chen said. ‘It was the world’s first electro-mechanical encryption device.’

‘Yes. In the world of cryptography people talk about ULTRA, because that was the name given to the cipher they used. But the machine those messages were created on was called Enigma, so it’s all the same thing.’

I smiled and said to Chen, ‘Just like you: your name is Chen Erhu but at work everyone calls you Bureau Chief Chen; it’s the same thing.’