Boris Solomatin Interview
During my career, I could have been or must have been a victim of several double agents cases - men who pretended to be spies. But after two or three of my people's meetings with them, I happily recognized them for what they were. The trick for a KGB agent to avoid being fooled is first of all to know enough about America to know what is secret and what is not secret. And that question often can be answered by asking this question: is the information being offered to me going to damage the country of the person giving it. For instance, in the case of John Walker, I knew that Norfolk was the East Coast main base for the U.S. naval fleet. I didn't know at the time much, but after meeting Walker I studied your Navy in detail. Also I did not and still do not know of a single instance when any intelligence service has used as a double agent a man with a sample of cryptography. Ciphers and code machines are too important, too sensitive for anyone to risk, even if they came up with a false example. Ciphers are too serious. The intelligence service cannot allow itself a game around such a serious matter.
There is something else to remember. Even if one service is feeding another service rubbish, a wise intelligence officer can learn much from that rubbish. Whether they send you true or false information - the fact that they send anything is a clue to how they think.
So when I saw the ciphers, which seemed to be real, I suspected that Walker was not a double agent.