Patent attributes
A method comprising, during runtime of an item of software that comprises one or more portions of code and verification code: the verification code generating verification data using (a) runtime data generated by the one or more portions of code and (b) one or more predetermined parameters, the verification data representing an element of a predetermined first set of data elements; and providing the verification data to an integrity checker arranged to (i) identify that a modification relating to the verification code has not occurred if the verification data represents an element of a predetermined second set of data elements, wherein the second set is a subset of the first set, and (ii) identify that a modification relating to the verification code has occurred if the verification data does not represent an element of the second set; wherein it is computationally infeasible to determine an element of the second set without knowledge of the one or more predetermined parameters or data related to the one or more predetermined parameters; and wherein, in the absence of a modification relating to the verification code, use of the one or more predetermined parameters by the verification code ensures that the verification data represents an element of the second set and use of the runtime data by the verification code controls which element of the second set is represented by the generated verification data.
