Post-Quantum Security of Block Cipher Constructions

Computer Science > Cryptography and Security [Submitted on 9 Oct 2025 (v1), last revised 14 Apr 2026 (this version, v2)] Post-Quantum Security of Block Cipher Constructions Gorjan Alagic, Chen Bai, Christian Majenz, Kaiyan Shi Block ciphers are versatile cryptographic ingredients that are used in a wide range of applications ranging from secure Internet communications to disk encryption. While post-quantum security of public-key cryptography has received significant attention, the case of symmetric-key cryptography (and block ciphers in particular) remains a largely unexplored topic. In this work, we set the foundations for a theory of post-quantum security for block ciphers and associated constructions. Leveraging our new techniques, we provide the first post-quantum security proofs for the key-length extension scheme FX, the tweakable block ciphers LRW and XEX, and most block cipher encryption and authentication modes. Our techniques can be used for security proofs in both the plain model and the quantum ideal cipher model. Our work takes significant initial steps in establishing a rigorous understanding of the post-quantum security of practical symmetric-key cryptography. Subjects: Cryptography and Security (cs.CR) Cite as: arXiv:2510.08725 [cs.CR]   (or arXiv:2510.08725v2 [cs.CR] for this version)   https://doi.org/10.48550/arXiv.2510.08725 Focus to learn more Submission history From: Chen Bai [view email] [v1] Thu, 9 Oct 2025 18:33:05 UTC (77 KB) [v2] Tue, 14 Apr 2026 22:03:52 UTC (78 KB) Access Paper: HTML (experimental) view license Current browse context: cs.CR < prev   |   next > new | recent | 2025-10 Change to browse by: cs References & Citations NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)