Quantum vs post‐quantum security for future networks: Survey

Classical cryptography schemes have been compromised by practical results on quantum computers in recent years. These schemes can now be broken using Shor’s algorithm. This paper provides a detailed survey of research on post quantum cryptography schemes, which are based on different principles and aim to reduce threats arising from advances in quantum computing. However, post quantum schemes do not completely solve the problem but instead represent a temporary solution. On the other hand, quantum cryptography and quantum key distribution, discussed in this paper, offer a more fundamental solution by relying on entanglement between quantum states. At least in the early stages, competition is expected between these two security approaches, so the paper provides a comprehensive survey of both quantum cryptography and post quantum cryptography algorithms, enabling a full understanding of their advantages and limitations when selecting implementation options for future networks. To further encourage network designers to consider quantum solutions for future networks, the paper presents original research on low earth orbit satellite network optimization algorithms for global quantum key distribution. The use of only low earth orbit satellites instead of combined low earth orbit and geostationary orbit systems, as previously considered, enables power savings of up to two orders of magnitude, which is important for implementation in power constrained terminals. The algorithms are designed using quantum search techniques such as Grover’s algorithm and quantum approximate optimization algorithms, which are particularly effective for solving combinatorial optimization problems.