Аннотация: One of the teaching materials for students. Based on the reading of Cryptonomicon.
Let me introduce you the endless world of cryptography. This science, or just the branch of human knowledge and activity, is extremely significant nowadays. You can be the unique owner of the information, which can decide the fates of the whole our civilization. It"s because the cryptography is the mathematical and programming tool to cipher and decipher data.
But together with common words I would like to describe you one of the cipher methods, which was used in the World War II. It is so called method of "cryptographic notebooks". In fact it"s just my own determination of this method, I even guess that you"ve heard a lot about this.
OK, here it goes:
The code as always bases on two main things: numbers of the letters and the letters themselves. For example you need to make secrecy of the word RUSSIA. Firstly you divide it on some nonsense parts like RUS SIA. Then you need to write down the numbers of every letter (you have to numerate the alphabet). Thus, we have 18 21 19 19 9 1. Secondly you need to have the special abracadabras (any letter combinations, appearing at your mind) at your notebook. The more often you change your abracadabra the more reliable is the code. Like DRE GVA. Thirdly you also numerate the letters of abracadabra. 3 18 5 7 22 1. Then you "connect" the numbers of the first line with abracadabra line. We get 21 39 24 26 31 2.
I guess that you have already gotten what the thing is about. We get the third, new line of the letters. But, after all, remember that in English only 26 letters are. So the bugger numbers must be decreased. Exempli gratia by dropping off the left parts of the numbers. So, finally we get 21 9 24 26 1 2. After "translation" we have UIX ZAB.
If only nobody knows your abracadabra it"s very difficult to understand your ideas, don"t you find?