Abstract: The present invention provides a central computer site on a computer network for detecting authorized or unauthorized duplication of software on computers connected to such a network. The computers on the network may be continually connected, like computers on a Local Area Network, or intermittently connected, like computers on the Internet. Every time a user of the distributed software attempts to execute that software, a connection to the central computer site on the network is made, and a previously-created information token is presented by the user's software to the central site. The central site evaluates that token, and possibly issues a new token to be kept by the user for the next transaction. These transactions need no human intervention, and may take place without the software user's knowledge. At the same time, the central site may provide or withhold permission for the user to execute the distributed software.