Patent ID: 7346780

Claim:
A method for facilitating the tamper-resistance of computer-executable instructions, the method comprising: first obtaining a first execution-identifying signature of a first program module, where the first program module includes hidden modification detection code for use in detecting code alterations, and where the first execution-identifying signature represents a first hash value generated by hashing an execution trace, the execution trace being a historical computation record which identifies how various morsels of data changed during multiple execution instances of the first program module with a specified first set of input parameters, the first execution-identifying signature therefore being based in part on execution of the hidden modification detection code included in the first program module, the first program module comprising one or more computer-executable instructions; second obtaining a second execution-identifying signature of a second program module, where the second program module includes the hidden modification detection code, and where the second execution-identifying signature represents an expected hash value generated by hashing an execution trace which represents multiple execution instances of the second program module with the specified first set of input parameters when no alteration has been made to the second program module, the second program module comprising one or more computer-executable instructions; and comparing the first and the second execution-identifying signatures to determine whether the first program module has been altered.