There is described a method of protecting an item of software so as to obfuscate a condition which causes a variation in control flow through a portion of the item of software dependent on whether the condition is satisfied, wherein satisfaction of the condition is based on evaluation of one or more condition variables. The method comprises: (i) modifying the item of software such that the control flow through said portion is not dependent on whether the condition is satisfied; and (ii) inserting a plurality of identity transformations into expressions in said portion of the modified item of software, wherein the identity transformations are defined and inserted such that, in the absence of tampering, they maintain the results of the expressions if the condition is satisfied and such that they alter the results of the expressions if the condition is not satisfied, wherein each identity transformation is directly or indirectly dependent on at least one of the one or more condition variables. New variables may be defined as part of this method. There are also described associated apparatuses, computer programs and the like.