A digital rights management system permits an application owner to cause code to be injected into the application's run-time instruction stream so as to restrict execution of that application to specific hardware platforms. In a first phase, an authorizing entity (e.g., an application owner or platform manufacturer) authorizes one or more applications to execute on a given hardware platform. Later, during application run-time, code is injected that performs periodic checks are made to determine if the application continues to run on the previously authorized hardware platform. If a periodic check fails, at least part of the application's execution string is terminated--effectively rendering the application non-usable. The periodic check is transparent to the user and difficult to circumvent.