Quantum Cryptanalysis: Breaking Classical Encryption with Shor's and Grover's Algorithms
Godwin Olaoye · 2025
The advent of quantum computing presents a paradigm shift in the field of cryptanalysis, challenging the security of classical encryption schemes that underpin modern digital communications. This study explores the capabilities of quantum algorithms, particularly Shor's algorithm and Grover's algorithm, in undermining widely used cryptographic systems. Shor's algorithm poses a direct threat to publickey cryptosystems such as RSA and ECC by enabling efficient integer factorization and discrete logarithm computation, which are computationally infeasible for classical computers. Meanwhile, Grover's algorithm provides a quadratic speedup for bruteforce attacks on symmetric-key cryptosystems like AES, significantly reducing their effective security. Through theoretical analysis and simulation-based evaluation, this paper highlights the vulnerabilities of classical encryption in the face of quantum advances and underscores the urgent need for post-quantum cryptographic solutions. The findings emphasize the critical importance of transitioning to quantum-resistant algorithms to ensure long-term data confidentiality in a future dominated by quantum technologies.