Practical realisation of a return map immune Lorenz-based chaotic stream cipher in circuitry

The authors report on the realisation of an encryption process in real-time analogue circuitry using on-the-shelf components and minimal processing power. Self-synchronisation of two similar systems through a single shared state is a unique property of the chaotic Lorenz attractor system. In this process, the single parameters of the system are modulated to mask a message before transmitting securely through a single-shared state. However, these techniques are vulnerable to the return map attack. They show that time-scaling can further obfuscate the modulation process and improve return map attack immunity and demonstrate a fabricated printed circuit board implementation of the system.