A method for increasing the tamper resistance of a computer software application comprises four steps. In the first step, a datum in the application to protect from tampering is chosen. In the second step, a location in memory into which the datum will be loaded when the application is executed is calculated. In the third step, user-purpose code to modify is chosen. In the fourth step, the chosen user-purpose code is modified so that, when executed, it reads a value from the memory location and uses it in useful calculation.