Patent ID: 6526456
Filing Date: 2003-02-25
Classification: G06F

Abstract:
A method of controlling use of a software product, comprising the steps of:obscuring a control thread in the software product; adding to the software product authorizing software and redirection software for recovering the control thread for an authorized subscriber; and supplying to an authorized subscriber, in response to execution of the authorizing software on execution of the software product, encoded subroutine reference information to enable the redirection software, during execution of the software product, to recover the obscured control thread in a manner that is dependent upon the environment of the authorized subscriber; wherein the redirection software is responsive to said encoded subroutine reference information to determine target addresses of calls to relocatable subroutines during rum-time execution of the software product, and the step of obscuring a control thread in the software product comprises replacing calls to said relocatable subroutines by calls to the redirection software, whereby at the authorized subscriber the software product is executed in dependence upon the redirection software without the software product ever being restored to its original form.