Scheme to defeat the use of switch boxes to illegitimately execute protected applications. The goal of a software protection scheme based on Sentinel keys is to significantly reduce the chance that someone can defeat the protection and use your software without the hardware key. This note describes a scheme to defeat the use of switch boxes to run a protected application on more than one system.
Switch boxes are devices that allow multiple computers to print to a single printer.
This scheme can only be used with a Sentinel key having memory. At application launch, compute a system number based on stable system attributes and store the number in the key . During execution of your application, do a security check of the system number and compare it to the stored number. Allocate a memory cell in the key to store the system number . Compute the system number based on current system attributes.