When Chaos Is Not Secure: Revealing Hidden Vulnerabilities in Chaotic Cryptography

Chaos-based cryptographic schemes have been widely investigated as lightweight solutions for image and multimedia security, owing to their nonlinear dynamics and high sensitivity to initial conditions. Despite these attractive theoretical properties, many such systems have been found to be susceptible to implementation-level vulnerabilities that remain undetected through purely mathematical analysis. In this study, a chaotic image-coding algorithm employing conditional XOR and XNOR operations was examined from a side-channel perspective. A profiling-based power simulation framework was developed to model the dynamic switching behavior of these gates, which are logically complementary but physically asymmetric. Distinct power signatures were observed for XOR and XNOR operations, allowing secret selection bits to be inferred with an average classification accuracy of 86.1%. The obtained results indicate that algorithmic unpredictability alone does not ensure resistance against physical leakage. It is therefore suggested that the design and validation of chaos-based cryptosystems should incorporate side-channel evaluation as an integral stage of development. The presented simulation framework can serve as a diagnostic tool for identifying gate-level asymmetries before hardware implementation. Future research is recommended to include hardware-level measurements, balanced logic synthesis, and automated leakage auditing in order to establish physically robust and cryptographically secure chaotic architectures.