We propose a passive keyless entry system which applies intra body communication and updating scheme. Re cently authentication vulnerability of the system has been reported. And most of attacks eavesdrop on authentication to extract the shared secret. The passive keyless entry system must be safe at least the life time of the vehicle. Our system uses in trabody communication instead of the wireless communication against eavesdropping. Furthermore in case the shared secret is extracted, our system updates the shared secret frequently.In this paper we describe the system design and the demo system.