US Patent 7840812 Authentication of digital certificates used by portable computing devices

A synchronization device checks the revocation status of a digital certificate used by a portable computing device, such as a personal digital assistant or mobile phone. The synchronization device typically sends the revocation status to the portable device during a periodic synchronization operation. Revocation status checking can occur using minimal processing, memory or network access resources of the portable device. In some embodiments, the synchronization device is a desktop personal computer, or a server within a mobile communication network. In other embodiments, the portable device uses a certificate and sends the certificate to the synchronization device during a subsequent synchronization operation. In yet other embodiments, the synchronization device checks the status of a certificate, generates a summary for the certificate and transmits the summary to the portable device prior to its use of the certificate. In yet other embodiments, the synchronization device manages certificates for one or more portable devices.