Virtual Leashing: Internet-Based Software Piracy Protection

Software-splitting is a technique for protecting software from piracy by removing code fragments from an application and placing them on a remote trusted server. The server provides the missing functionality but never the missing code. As long as the missing functionality is hard to reverse-engineer, the application cannot run without validating itself to the server. Current software-splitting techniques scale poorly to the Internet because interactions with the remote server are synchronous: the application must frequently block waiting for a response from the server. Perceptible delays due to network latency are unacceptable for many kinds of highly-reactive applications, such as games or graphics applications. This paper introduces virtual leashing, the first non-blocking software-splitting technique. Virtual leashing ensures that the application and the server communicate asynchronously, so the application´s performance is independent (within reason) of large or variable network latencies. Experiments show that virtual leashing makes only modest demands on communication bandwidth, space, and computation