Insider-Attacks on Physical-Layer Group Secret-Key Generation in Wireless Networks

J. Harshan, Sang-Yoon Chang, Yih-Chun Hu
2017 2017 IEEE Wireless Communications and Networking Conference (WCNC)  
Physical-layer group secret-key (GSK) generation is an effective way of generating secret keys in wireless networks, wherein the nodes exploit inherent randomness in the wireless channels to generate group keys, which are subsequently applied to secure messages while broadcasting, relaying, and other network-level communications. While existing GSK protocols focus on securing the common source of randomness from external eavesdroppers, they assume that the legitimate nodes of the group are
more » ... ed. In this paper, we address insider attacks from the legitimate participants of the wireless network during the key generation process. Instead of addressing conspicuous attacks such as switching-off communication, injecting noise, or denying consensus on group keys, we introduce stealth attacks that can go undetected against state-of-the-art GSK schemes. We propose two forms of attacks, namely: (i) different-key attacks, wherein an insider attempts to generate different keys at different nodes, especially across nodes that are out of range so that they fail to recover group messages despite possessing the group key, and (ii) low-rate key attacks, wherein an insider alters the common source of randomness so as to reduce the keyrate. We also discuss various detection techniques, which are based on detecting anomalies and inconsistencies on the channel measurements at the legitimate nodes. Through simulations we show that GSK generation schemes are vulnerable to insiderthreats, especially on topologies that cannot support additional secure links between neighbouring nodes to verify the attacks. Index terms-physical-layer security, secret key generation, group keys, insider attacks 978-1-5090-4183-1/17/$31.00 ©2017 IEEE
doi:10.1109/wcnc.2017.7925526 dblp:conf/wcnc/HarshanCH17 fatcat:dcasrxk7onao3cnjlduenwteiy