Improved arithmetics in software protection

For protecting the software designer's rights,improved arithmetics for software limited use and register engine have been discussed.In the limited use arithmetic,it gives up the normally used method which counts the days between the date of software installation and now,replaced by a new one which counts the different date since the latest use.This arithmetic is more reasonable and unpredictable.In the register engine arithmetic,it introduces a valuable One Computer One Code method,combineing with multilevel shift encrypting,it can implement a better protection effect.