While he was explaining this, he was pointing to the columns of figures written up around the room like a hoard of ants. Sometimes his finger moved, sometimes it was still, as if he were gradually working his way through to the very heart of the matter.
To tell you the truth, I was astounded by his idea of the twin paths. I understood immediately that although in principle these two paths had to exist, in actual fact they might well not exist at all. Maybe nobody else realized, but if you treated those paths as strings and pulled on them, the person tugging would in the end find himself garrotted. .
Of course I will explain what I mean. Tell me, what does it feel like when you walk closer and closer to a bonfire?
Exactly. You will feel a hot, burning sensation. After that, you do not dare to get too close; you want to preserve a certain distance, so that you won’t get burned again. The same principles apply when you get close to a person — the influence that a particular person exerts over you depends on their individual attractiveness, character and capacities. I can tell you categorically, regardless of whether you are talking about a person who creates ciphers or a person who decrypts them, cryptographers are the most remarkable people, with really unusual capacities — their minds are like black holes. Any one of them is capable of exerting an enormous influence upon their fellows. When you walk into the forest that is a cipher, it is like walking through a jungle in which there are countless traps — at every step you run the risk of falling into one and not being able to get out again. That is why those who create ciphers (just like those who unlock them) don’t dare think too much about the history of encryption, because each concept, each theory in the history of this field can attract you like a magnet; can destroy you. The minute your attention has been distracted by one of these concepts, you are worthless as a cryptographer, because ciphers cannot have any intrinsic similarity to one another, to prevent them from being cracked too easily. Any similarity would make the two ciphers so much rubbish — ciphers are indeed heartless, mysterious things.
Well, now you can see why I was so amazed — the two paths theory that Rong Jinzhen had developed resulted in him disobeying one of the cardinal rules in cryptography. I don’t know whether he was ignorant of it, or whether he knew and decided to go ahead anyway. Given the first shock that he had caused me, I think that it is most likely that he knew and had decided to go ahead regardless — he was intentionally breaking one of our cardinal rules. When he hung the diagrams he had worked out from the history of cryptography up on his walls, he was demonstrating that he was of no mean intelligence. He was breaking the rules not because he was stupid and ignorant, but because he knew exactly what he was doing and was brave enough to go ahead with it.
When I heard his two paths theory, I didn’t criticize him the way that maybe I ought to have — I was struck with a kind of silent admiration, not unmixed with jealousy, because he was clearly way ahead of the rest of us.
At that time, he had not even spent six months in the cryptography unit.
I was very worried about him, because it seemed to me that he was in a very perilous situation. As you will now realize, Rong Jinzhen wanted to tug on the two strings that he had found — that meant that he was proposing to become entrenched behind every concept and theory in the history of cryptography, cutting his way through each of the countless layers of evolution to reach to the underlying principles. Every single layer would represent endlessly attractive theories and concepts, any one of which might lay its dead hand upon his mind and turn everything that he had done into worthless rubbish. That is why for so many years there had been one unwritten rule in cryptography: Avoid history! Everyone was perfectly well aware of the fact that there — in the history of the subject — there was no doubt any number of opportunities and pointers to help decrypt modern ciphers. But the fear of going in and not being able to find a way out overcame all other considerations — that was more important than any information to be found therein.
If I may put it in these terms, the forest that is the history of cryptography is very silent and very lonely. There are no people there to ask the way from; nobody would dare to ask for directions! This is one of the tragedies of cryptography — they have lost the mirror of history, they have lost the sense of community that comes from planting the same seeds and harvesting the same fruit. Their work is that difficult and mysterious; their souls are that lonely and alienated — they cannot even climb on the bodies of those who went on ahead. At every stage they are faced with closed doors, with mantraps, forcing them to travel by side roads, to avoid any open path. For history to have become a troublesome burden to later generations. . what an unhappy state of affairs! That is the reason why so many geniuses have been buried within the borders of cryptography — the number is appallingly high!. .
. . Okay, let me explain this in simple terms. The usual way that cryptography proceeds is by a slow process of elimination: the first thing that happens is that intelligence agents collect a load of relevant information and you then try and use this information to develop hypotheses — this feels very much like using a limitless number of keys to open a limitless number of doors. You have to design and make the keys and doors yourself — how endless the task is in practice is determined by how much material you have to work with; it is also determined by how sensitive you are to the cipher you are working with. I should explain that this is a very simple and stupid way of proceeding, but it is also the safest, the most secure, and the most effective. This is particularly the case when you are trying to decrypt a high-level cipher. Given the comparatively high success rate, this method is still in use today.
But Rong Jinzhen, as you understand, was not interested in doing it the traditional way. He had gone rushing straight into forbidden territory — in spite of the fact that he was a cryptographer he was immersing himself in the history of the field, standing on the shoulders of the giants of previous generations, and the only result to be expected from this was a terrible, frightening one. Of course if it worked, if he was able to come and go through every trap set by cryptographers of old, that would be a genuinely unbelievably impressive achievement. At the very least he would be able to narrow the focus of his search. Say for example that if there were 10,000 little byroads, he might be able to eliminate one half by this process — maybe less. The number that he would be able to eliminate would determine the prospect of success for his approach. That would decide how feasible it would be to put his two path theory into practice. To tell the truth, the success rate for such a thing was so low that very few people tried it and the ones that had succeeded were as rare as morning stars. In the world of cryptography, there would only be two types of people prepared to run so great a risk. One would be a genius, a real genius, and the other would be a lunatic. A lunatic is afraid of nothing, because he does not understand that the thing is genuinely frightening. A genius is afraid of nothing, because he knows he is armed with unusual weapons. Once he has made up his mind to the task, any difficult or dangerous obstacle can be overcome.
To tell you the truth, at that time I was not sure if Rong Jinzhen was a genius or a lunatic, but there was one thing that I was absolutely certain of — I was not going to be surprised if he turned out to do amazing things or did nothing at all; whether he became a hero or the whole thing ended in tragedy. So when he decrypted PURPLE without a word to anyone, I was not surprised at all — I just felt a great relief on his behalf. At the same time I was so impressed I really felt like getting down on my knees and kowtowing to him.