A pH Sensing System with Security Enhanced Cryptographic System

Integrated compact sensor systems are essential in many applications. However, the design focus is on sensor performance metrics and encryption of the wireless signals is usually an afterthought. Encryption is typically implemented with the help of digital gates or software approaches. In this paper, a quasi-digital pH sensor system with a cryptographic system that enhances the security of the overall sensor system is demonstrated. The encryption-decryption uses a double scroll-like chaotic topology that is implemented with analog circuits. The circuits were implemented using a commercial 180 nm technology. The pH sensor had a sensitivity of 50 MHz/pH, and consumed 3.03 mW power. The chaotic circuit module consumed 6.1 mW power.