Executing an obfuscated application program comprises receiving an application program comprising application program instructions and application program data, determining an application program instruction location permutation to apply to a current instruction counter value, determining an application program data location permutation to apply to a current data location counter value, receiving the current instruction counter value, and applying the application program instruction location permutation to the current instruction counter value to obtain a reference to an application program instruction in an instruction stream to execute. If the application program instruction references application program data, the application program data location permutation is applied to data referenced by the application program instruction to obtain a reference to data to access. The data to access is interleaved with application program instructions in the instruction stream. The application program instruction is then executed.