Post-quantum attacks against symmetric-key cryptography systems

• Main Author: Pham, Thi Minh Phuong
• Other Authors: Guo Jian
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Computer and Information Science; Quantum attack; Symmetric-key; Constraint programming; Advanced encryption standard
• Online Access: https://hdl.handle.net/10356/174201
• Institution: Nanyang Technological University

Contemporary cryptography plays an essential role in the security of digital communication, internet, and data storage. The level of security of a cryptosystem is measured by the computational resources needed to break it. Traditional cryptanalysis focused on analyzing and breaking cryptographic systems, with the aim of uncovering their weaknesses and vulnerabilities using classical computers. However, the emergence of quantum computing introduces a need to revise these security levels, considering a completely new set of algorithms. The main objective of this thesis is to explore the security aspects of block ciphers and hash functions, considering both traditional and quantum computing environments. Through the utilization of automated tools and quantum techniques, various attacks, such as distinguishers and collision attacks, were employed to evaluate the security levels of these fundamental cryptographic components. Firstly, we introduced quantum multi-collision distinguishers that enabled us to target a higher number of rounds on AES-like primitives. These distinguishers were developed by using constraint programming tools to automatically identify the related-key or single-key di erentials used in the attacks. This approach led to the discovery of several novel distinguishers for round-reduced AES, Saturnin, and Rijndael, expanding our understanding of their vulnerabilities. Next, building upon the observation that multi-collision attacks can be trans- formed into collision attacks, we adapted our automated tools to facilitate collision attacks. By incorporating the rebound techniques and the degree of freedom from keys and states to our model, we achieved significant advancements in the number of attacked rounds, ranging from one to five, in various target systems such as AES-128, Saturnin hashing mode, Grøstl-512, and SKINNY-hash. Finally, we expanded our investigation by integrating the degree of freedom from the tweak into our model. This innovation allowed us to create a unified related-key di erential search, enabling us to uncover new chosen-key distinguishing attacks on full-round AES, Kiasu-BC, and Deoxys-BC.