Methods for preventing unauthorized software distribution

In this paper we present algorithms for protecting software from unauthorized installation. We assume that the user buys software on a disk or downloads it from the Internet — although our methods are not limited to protecting software under these circumstances. We consider two kinds of adversaries. One kind of attacker is a sophisticated hacker who can monitor a line and can read and intercept any information flowing unprotected over the Internet. These attackers are also skillful programmers who can analyze the software, locate any data of interest to them and also write and execute any programs, even the most complicated ones. Another kind of attacker is an average attacker who can copy and use personal or business software.