Performance Enhancement of RSS-Based Secret Key Generation using Lightweight Minimal Bit Syndrome Reconciliation Method for IoT Devices

Abstract

Secure communication in Internet of Things (IoT) devices can be improved through physical-layer 
secret key generation. In secret key generation, an information reconciliation process is required to match the 
bit sequences between the two communicating devices. However, this process often involves complex statistical 
computations that increase system overhead and require the transmission of bits over an insecure public 
channel. Therefore, this research presents a lightweight reconciliation algorithm based on minimal bit 
syndrome to reduce overhead and improve key security. The proposed method processes quantized Received 
Signal Strength (RSS)  values into 8-bit block syndrome-based reconciliation mechanism and only the 8-bit 
syndromes from mismatched block are transmitted over the public channel. System testing was conducted 
under both static and dynamic scenarios in an indoor area using Raspberry Pi nodes. The results show that 
the proposed scheme demonstrates an improvement in the Key Generation Rate (KGR) by 2.2% and reduces 
the processing time by 11.6% in dynamic scenario and 8.3% in the static scenario. Also, the proposed scheme 
reduce the quantization and reconciliation time by 50% compared to previous research. Furthermore, the 
proposed method maintained a Key Disagreement Rate (KDR) of 0% across all block size and successfully 
passed the NIST randomness and complexity test, with all test parameters achieving p-values above 0.01. 
These result indicate that the proposed scheme improve the performance of existing secret key generation 
methods and it is suitable for implementation in IoT devices.