Patent ID: 6343280
Filing Date: 2002-01-29
Classification: G06F

Abstract:
A method of preventing unauthorized use of an executable file comprisingselecting from said executable file sequences of instructions, creating a modified executable file by replacing each of said selected sequences of instructions with instructions that interrupt the normal flow of execution, installing said modified executable file in a first computer, installing said selected sequences of instructions in a license server, executing said modified executable file in said first computer until one of said instructions that interrupt the normal flow of execution is encountered, communicating said first computer's machine state to said license server, determining in said license server whether said first computer is authorized, executing one of said selected sequences of instructions in said license server if said first computer is authorized, communicating the results of said license server's execution of said one of said selected sequences of instructions to said first computer, and continuing execution of said modified executable file in said first computer until another of said instructions that interrupt the normal flow of execution is encountered or until execution of said modified executable file is complete; wherein said machine state comprises the contents of the CPU registers and the program counter value, and wherein said license server emulates operation of said first computer when said license server executes said one of said selected sequences of instructions in said license server.