Hybrid Classical-Quantum Rainbow Table Attack on Human Passwords

Abstract: Passwords that are long and human-generated pose a challenge for both classical and quantum attacks due to their irregular structure and large search space. In this work, we present an enhanced classical-quantum hybrid attack tailored to this scenario. We build rainbow tables using dictionary-based password generation with transformation rules to better model real user behavior. These tables are then organized into buckets, enabling faster lookup and reduced space complexity. To perform quantum search within each bucket, we use a distributed exact variant of Grover's algorithm, which offers lower circuit depth and deterministic success. As a result, the overall quantum circuit is shallower and more robust against noise, particularly from depolarizing channels commonly found in near-term quantum devices. Through this work, Overall, we propose a hybrid framework that combines structured rainbow tables with efficient quantum search to enhance password recovery.