US Patent 7340600 Authorization infrastructure based on public key cryptography

A public key authorization infrastructure includes a client program accessible by a user and an application program. A certificate authority issues a long-term certificate that binds a public key of the user to long-term identification information related to the user. A directory stores the issued long-term certificate and short-term authorization information related to the user. A credentials server issues a short-term certificate to the client. The short-term certificate binds the public key to the long-term identification information and to the short-term authorization information. The client presents the short-term certificate to the application program for authorization and demonstrates that the user has knowledge of a private key corresponding to the public key in the short-term certificate. The short-term certificate includes an expiration date, and is not subject to revocation.