"engenders" - 1 õppematerjal

TheCodeBreakers

The relation between cryptography and cryptanalysis is not logically necessary; it is contingent. One can envision men communicating by secret means with others not even thinking of prying. But in the real world, the cryptanalyst —or more accurately the potential cryptanalyst— comes first. What need for cryptography if no one would eavesdrop? Why build forts if no one would attack? Thus the assumption that someone will attempt a cryptanalysis, no matter how tentatively or incompetently, engenders cryptography.  Experience of the interreaction between cryptography and cryptanalysis has precipitated out certain practical principles. They all refer to time, because all practical matters involving mortal men connect eventually with that one inexorable, irreversible, irretrievable factor. Time, for the cryptographer, controls a variable relationship. The most general of the cryptographer's principles deals with the sliding ratio