Low-Complexity Compressed-Sensing-Based Watermark Cryptosystem and Circuits Implementation for Wireless Sensor Networks

摘要

The emerging compressed sensing (CS) technique provides lightweight data compression with zero-cost encryption. Therefore, CS enables reduced-complexity designs for sensor nodes and saves transmission power in wireless sensor networks (WSNs). However, CS's linear encoding process makes it vulnerable to several attacks, which may lead to privacy leakage issues. In this article, leveraging the characteristic that CS reconstruction is sensitive to measurement noise, we propose a CS-based watermark cryptosystem for WSNs. In the front-end sensor, a low-dimension watermark is embedded in measurements. In the back-end solver, we present a CS-based watermark decryption/reconstruction engine for the Internet of Things (IoT) gateway. Without synchronization of the key, the proposed cryptosystem can resist ciphertext-only attack and known-plaintext attack effectively. Furthermore, leveraging watermarks as a digital signature, the proposed engine can detect denial of service attack effectively before signal reconstruction. For real-time signal processing, multiple-indices updating algorithm and VLSI architecture are applied to eliminate the throughput degradation from watermark removal. Finally, this CS decoder is fabricated in 40-nm CMOS, and it can support the simultaneous reconstruction of over 10 000 wireless sensors in real time while offering synchronization-free watermark decryption. Therefore, the proposed cryptosystem is suitable for the emerging IoT applications that need encryption strength with limited complexity.