Document Type : Research Paper

Author

• MohamadAli Khajeian

University of Tehran

Abstract

Long, human-generated passwords pose significant challenges to both classical and quantum attacks due to their irregular structure and large search space. In this work, we propose an enhanced classical–quantum hybrid attack specifically designed for this scenario. Our approach constructs rainbow tables using dictionary-based password generation augmented with transformation rules that better capture real-world user behavior. These tables are organized into buckets, enabling faster lookup and reduced space complexity.
For the search within each bucket, we employ a distributed exact variant of Grover’s algorithm. This method provides deterministic success and significantly lower circuit depth, enhancing robustness against noise—particularly depolarizing errors common in near-term quantum devices.
Overall, our hybrid framework improves the efficiency and practicality of password recovery for long, human-readable passwords in realistic adversarial settings.

Keywords

• Rainbow Table Attack
• Grover's Algorithm
• Human Password Recovery
• Hybrid Quantum-Classical Attacks
• Quantum Security