Advertisement authentication system in which advertisements are downloaded for off-line display

摘要

A system and method for authenticating that advertisements are properly displayed at a remote computer. The advertisements are received electronically and are stored in a memory device at the remote computer. The advertisements are output to users when the remote computer is off-line. Each advertisement is authenticated by the remote computer prior to output to ensure, for example, that the advertisement has not been tampered with, modified or replaced. Information as to when advertisements are output is recorded and used for billing the advertisers. This information can be stored in a statistics file on the remote computer. When the statistics file is transferred to a central computer, the statistics file is authenticated to ensure that it has not been tampered with, modified or replaced. The authentication scheme can be used as part of an electronic mail system.