Application and research on cryptography of guard against theft

This paper introduces the history, classes and characters of cryptography and indicates the necessity of guard against code theft. In order to protect just identity and secret information, a new kind of cryptography and its application and advantages has been given and analyzed. To develop a better character of guard against theft, the operator must rightly use fixed first code with validation code which is decided by algorithm of each time to pass identity verification. The paper illuminates the theory of software control, puts forward a novel secure cryptography that has not been found before.