This disclosure describes a key update scheme for use in a mobile IP network. The update scheme may be implemented to facilitate key updates between a mobile device and a server computer that authenticates the mobile device. The techniques described herein can facilitate key updates in a manner that accounts for potential message loss during the update routine, mobile device failure during the update routine, or other problems typically encountered in a mobile network settings. In this manner, the techniques can provide a robust scheme for key updates and may improve network security.