Post-quantum security of cryptographic transformations in the random oracle model

Huang, Y. (2026)

Doctoral Thesis

In cryptography, generic transformations are often used to strengthen simpler but weaker schemes, into more sophisticated and stronger ones. This thesis aims to establish rigorous, provable notions of security for various such transformations that are relevant in the scope of post-quantum cryptography. We achieve this via formal mathematical proofs, and in some cases, via proposing new security definitions, when existing ones are inadequate. Most analyses are treated in an idealized setting known as the random oracle model.

• Post-Quantum Cryptography
• Random Oracle Model
• Quantum Random Oracle Model
• Cryptographic Transformations
• Provable Security
• Fiat-Shamir with Aborts
• Hash-and-Sign with Retry
• BUFF Transform
• KEM Combiner

• All authors: Huang, Y.
• Supervisor: Fehr, S.O.; Cramer, R.J.F.
• Committee: Agrawal, S.; Majenz, C.; Vaudenay, S.; Derks, G.L.A.; Luijk, R.M. van
• Qualification: Doctor (dr.)
• Awarding Institution: Mathematical Institute (MI), Faculty of Science, Leiden University
• Date: 2026-04-01
• ISBN (print): 9789061964322
• DOI: doi:10.60602/1887-4300382
• Sponsorship: NWO
• Grant number: NWA.1215.18.002