A Secure Communication System in Self-Organizing Networks via Lightweight Group Key Generation

Self-organizing networks provide rapid and convenient networking for many situations and have gained extensive research. With the progress of researches, security issues have attracted people's attention. There is no central node in self-organizing networks, and therefore the traditional key distribution methods based on public infrastructure do not work. The standardized pre-shared keys have predictable security risks. The physical-layer secret key generation has become a technology worth considering due to its lightweight, security, and decentralization. However, most of the previous work has focused on two devices, and remains a challenge to expand the pairwise key into the group key. Since the channel reciprocity only exists between two devices, some information would be exchanged on the unencrypted channel, causing information leakage. This paper designs a secure communication system in self-organizing networks. It adopts an adaptive quantizer to generate the pairwise keys and proposes DORCE, Difference Of quantization Results at one deviCE. The authenticated users share the group key via the difference between pairwise keys. The algorithm is implemented in a mesh topology, which is suitable for self-organizing networks because users' joining and leaving will not have a great impact on the network topology. The algorithm's Key Achievable Rate is up to 4 bits. Experimental results demonstrate that DORCE can generate the group keys in seconds. The Key Generation Rate is above 10 bits per second, enabling a group key generation to be used in a communication system for self-organizing networks. All the generated keys pass the NIST Statistical Test Suite.