| 摘要 |
<p>An authentication server is provided which stores authentication details of authorised users, and a list of currently-authenticated users. A number of application servers are connected to the authentication server, to allow the application servers to check the current authentication status of a user which requests service by the application servers. A session key is generated during the authentication procedure, for use during subsequent communications. One embodiment of application server which is adapted for use in combination with the authentication server is a file transfer server which allows authenticated users to upload files using a first session key generated during authentication of the sending user, and which allows a recipient to retrieve the file in encrypted form using a second session key which is generated during the authentication of the second user. The file transfer server also allows a file sender to specify a release date for data transmitted to the server. In one embodiment, the transmitted file is doubly encrypted using not only the session key of the recipient, but also an encryption key which is released to the recipient only after the specified date and time. In another embodiment, the file is stored on the server until such time as the specified date and time have passed, before being released to the recipient.</p> |
