In the era of quantum computing, the cryptography landscape is undergoing a paradigm shift. This chapter investigates the application of quantum algorithms to break classical block ciphers, a fundamental component of secure data communication. Traditional block ciphers, designed to withstand attacks from classical computers, face unprecedented threats from quantum adversaries capable of exploiting Shor’s algorithm for integer factorization and Grover’s algorithm for unstructured search. This research explores the theoretical underpinnings of quantum cryptanalysis applied to block ciphers and evaluates the potential impact on widely adopted symmetric-key encryption algorithms. We present a detailed analysis of the vulnerabilities introduced by quantum algorithms and discuss the implications for the security of encrypted data in the post-quantum era. Our study delves into the quantum oracle model, quantum key search, and other quantum algorithms relevant to the cryptanalysis of block ciphers. We provide insights into the cryptographic primitives and constructions that may be more resilient in the face of quantum attacks, paving the way for the development of quantum-resistant cryptographic solutions. Furthermore, we discuss the practical aspects of implementing quantum attacks on block ciphers, considering the current state of quantum computing technology. This research contributes to the ongoing dialogue on the intersection of quantum computing and cryptography, offering valuable insights into the challenges and opportunities presented by the quantum threat to classical block ciphers.