Exploring the Feasibility of Physical Layer Key Generation for LoRaWAN

Pedro Cruz, Ricardo Suyama, Murilo Loiola

Weitao Xu, Sanjay Kumar Jha, Wen Song Hu

Physical layer key generation that exploits reciprocity and randomness of wireless fading channels has attracted considerable attention in recent years. Despite much research efforts in this field, the problem of wireless key generation at long distance and low data rate remains unknown and has not been studied. In this paper, we conduct extensive experiments and analysis in real indoor and outdoor environments to explore the feasibility of wireless key generation for Long Range Wide Area Network (LoRaWAN). Based on the results, we present LoRa-Key, the first complete key establishment protocol for LoRaWAN by exploring the shared randomness extracted from measured Received Signal Strength Indicator (RSSI). LoRa-Key employs a number of signal processing techniques to improve key generation rate significantly. Experimental results show that LoRa-Key can achieve key establishment rates of 13 bit/s in stationary scenario and 21 bit/s in mobile scenario. To the best of our knowledge, this is the first work that studies key generation protocol for LoRaWAN.

Hong Qiang Zhao, Enting Guo, Zhuotao Lian +3 more

Girones De La Fuente, Andreu

This work analyzes the behavior of physical layer security in a LoRaWAN. For this purpose, a testbed is designed and implemented. The testbed had two main participants, Alice and Bob. Each one was transmitting over the LoRa protocol. For the generation of the symmetric keys, based on the channel perceived by Alice and Bob, the RSSI measure was chosen as the channel parameter to be quantized. For the quantization process, two different quantizers were used. Those are the threshold-based quantizer and the difference-based quantizer. Furthermore, when the results are discussed, its performance is compared. Also, we analyze how the performance of both quantizers is when the key generation was based on samples that present different correlations between Alice?s and Bob?s measures.

Ehsan Olyaei Torshizi, Anas Alashqar, Werner Henkel

Biao Han, Yahui Li, Xiaoyan Wang +2 more

The security of Low-Power Wide-Area Network (LPWAN) mainly relies on encryption for ensuring packet integrity and confidentiality. Unfortunately, the latest LPWAN specifications refrain from specifying how to distribute keys for encryption. In this paper, we tackle this problem via physical layer security, which exploits the channel characteristics to generate secret keys at the physical layer. In order to generate consistent keys from noisy feature sources and to achieve high reconciliation success rate, we propose FLoRa, a physical layer key generation system for LPWAN based on sequential fuzzy extractor. An adaptive multi-bit quantization algorithm is first proposed to generate the initial key, which accelerates the bit generation rate at the start-up procedure. We then design a novel fuzzy extractor by sequentially slicing the initial key, which improves the reconciliation success rate, as well as reduces the key reconciliation time. We implement FLoRa in a LoRaWAN based network prototype and evaluate it by conducting extensive indoor and outdoor experiments. Experimental results reveal that FLoRa is capable of generating consistent secret keys with high key generation performance in both static and dynamic network environments.