Quantum Cryptanalysis: A Survey of Threats and Post-Quantum Countermeasures

Quantum computing will revolutionize the power of computation, solving problems that currently have no solution classically. Such a jump in computational power presents an existential threat to modern cryptography, particularly public-key systems that rely on factoring and discrete logarithmic problems. This paper presents the emerging area of PQC countermeasures and gives a survey of quantum cryptanalysis methods. A literature review of progress from 2010 to 2025 is also provided, specifically addressing the advancement of algorithms, standards and applications. For universal security of data in the quantum age, they add, it will be critical to transition to quantum-resistant infrastructures.