Efficient Geometric Group Key-sharing Scheme

In recent years, Internet of things (IoT) technologies that are used to collect various data have advanced significantly. In such networks, devices communicate with each other to exchange data. It is efficient for group-encrypted communication in IoT networks when devices in a group communicate with a common group key. However, if one device in the group is analyzed by an attacker, the group key is leaked. Therefore, a group key-sharing scheme that can change the group composition including a device deletion is required. Hamasaki et al. proposed a group key-sharing scheme using geometric characteristic. In this scheme, each device stores only the unique key and the key generates the coordinates for key sharing. The group composition can be changed easily using this scheme. However, the scheme incurs considerable computation cost when a large number of devices exist in the group. Therefore, we propose an efficient scheme that improves on Hamasaki et al.’s scheme for group key sharing and compare it with other methods.