Cryptography – science which is engaged in ways of enciphering of information. Now for protection of confidential data the text of the message is transferred to the code from numbers which only the addressee can decipher.
The cryptography can reliably protect information from multinational corporations, mafia and the state espionage. With active information technology development more and more companies transfer the activity to a world wide web. At data transmission the cryptography is engaged in ensuring information security.
Cryptography history
Cryptographic information security arose still in the ancient time. Presumably enciphering of letters appeared at the time of Ancient India, China and Egypt. The known examples of the cryptographic code which reached our days are Aeneas's plate, Polibiya's square, Caesar's code.
The way of substitution was the most widespread method of ancient enciphering. The number, the pictogram or other letter was assigned to each letter of the alphabet. The leaf with these data is called a key. The owner of a key could both decipher, and to encrypt the message. During time the codes became harder and harder, instead of manual comparison of letters and symbols special cipher machines appeared. Rapid development of use of cryptographic codes began during World War II. The cryptography as information security is at the moment especially relevant. The reason is that in recent years use of computer networks extended, on them transfer private, state, military and commercial information. For information security there were new powerful computers, but the same computers can be used for breaking of the code, its decoding.
Modern methods of cryptography
Transfer of a key was one of problems of cryptography. That the person could read the coded message, he had to receive a key from the creator of the code in the beginning. And if the creator and the recipient were at a great distance, the probability of interception of a key by the third parties was very high. A solution of this problem was found in the seventies the last century. By means of computers it became possible to transform symbols to numbers and to make with them mathematical calculations. The way of coding at which two keys are used was invented. The open key is known to all, and closed only to the recipient. Information is coded by means of an open key and in the form of numbers goes to the addressee. The recipient can decipher data, having substituted in mathematical function variables in the form of the message and the confidential closed key. This way of enciphering made a revolution in cryptography and made the information transferred to it not only confidential, but also complete and neotkazuyemy. The method of asymmetric keys is not deprived of shortcomings and usually it is supplemented with other ways of protection.