Patent ID: 9055437
Filing Date: 2015-06-09
Classification: H04L,H04W

Abstract:
1. A communication system comprising: UE (User Equipment) and an HLR (Home Location Register) used in an IMS (IP Multimedia subsystem) network; and a femtocell base station that constructs a predetermined communication area, wherein said femtocell base station exists between said UE and said HLR, acquires a concealment key corresponding to said UE from said HLR during authentication of said UE, and executes a concealment process to conceal the identity of said UE based on said concealment key, wherein said concealment key is used to conceal the identity of said UE just for communication between said UE and said femtocell base station, wherein a controller of the system comprises: an acquirer that acquires a RAND (Random challenge), an AUTN (Authentication Token), an XRES (Expected RESponse), an IK (Integrity Key), and a CK (Cipher Key) corresponding to an IMSI of said UE from said HLR as the concealment key; a first generator that generates an MK (Master Key) based on the IK and the CK acquired by said acquirer and the IMSI of said UE in a first message; a second generator that generates an MSK (Master Session Key), an EMSK (Extended Master Session Key), K_encr, and K_aut based on the MK generated by said first generator; a third generator that generates a MAC (Message Authentication Code) based on the K_aut generated by said second generator; and a third communicator that transmits a second message including the MAC generated by said third generator, the RAND and the AUTN acquired by said acquirer, and the CK and the IK generated by said first generator as the concealment key.