Exploring Grover’s Algorithm in brute force attacks

This thesis investigates the practical use of a quantum algorithm known as Grover's Algorithm in brute force attacks. Grover's Algorithm theoretically provides a quadratic speedup for search problems, which also applies to brute force attacks, posing significant security implications on cryptography. The thesis will introduce cryptography, especially symmetrical encryption, as well as the basics of quantum computing, Post Quantum Cryptography (PQC) and brute force attacks. In addition, Grover's Algorithms functionality, its current research status and theoretical impacts on cryptography are further examined.

To demonstrate the current status of the algorithm in a practical setting, a series of brute force attacks utilizing Grover's Algorithm were executed on a Quantum Processing Unit (QPU) and on quantum simulators. The implementation focused on brute forcing an 8-bit secret key, in addition to investigating the impact of scaling the attack to longer key lengths. A series of classical brute force attacks using similar parameters were also executed to provide performance benchmarks. The quantum circuit implementation was developed using the Qiskit framework, while the IBM Quantum Platform provided access to the used quantum backends.