Patent ID: 9654284
Date: 2017-05-16
CPC Classifications: H04L,H04W

Claim:
1. A method for computing a group key for a group of machine type communication devices in an apparatus, comprising: computing, by the apparatus, an intermediate group key based on unique identifications of member devices of the group of machine type communication devices; computing, by the apparatus, an authentication item on the basis of the intermediate group key and a random value; sending, by the apparatus, the random value to the member devices of the group not acting as a gateway device performing authentication and key agreement procedure for the group; receiving, by the apparatus, key materials from the member devices computed based on the random value and the unique identifications of the member devices; authenticating the member devices on the basis of the received key materials and the authentication item computed on the basis of the intermediate group key and the random value; and computing, by the apparatus after said authenticating, the group key from the materials of the member devices and a unique identification of the gateway device, wherein communication between the apparatus and a network application function is performed by using a session identification of the group, and/or by using a session identification of a member device of the group, generated based on the session identification of the group and the unique identification of the member device.