Implementation of Multi-Positional Key Mismatch Attacks Against NIST Post-Quantum KEMs

Adrian Åström ()

Beskrivning

In 2016 NIST announced the Post-Quantum Cryptography Standardization Project to combat the quantum-threat to the major, widely used cryptosystems. Among the proposed quantum-secure schemes were Kyber, a module-LWE cryptosystem, which won the competition and became the new standard for PKE/KEM in 2022.

In the selection process, the so-called misuse resilience was an important consideration and as a contribution to the standardization project, researchers have presented key mismatch attacks against the CPA-secure version on Kyber. In 2021 Qin, Y. et al. showed a one-positional key mismatch attack, and in 2022, Guo, Q. and Mårtensson E. presented an improved attack targeting pairs of coefficients of the secret key in every query. In 2024 Q. Guo, E. Mårtensson and A. Åström presented the Adaptive and Parallel Attack, an attack where multiple coefficients of the secret key are recovered in parallel utilizing an offline PC-oracle. The attack is adaptively selecting which coefficients to target in each query, making it more efficient per query. As a tool for analysis and verification of the properties of the attack the researchers wanted an implementation of a simulation of this attack.

In this master’s thesis, such a tool is presented and explained in detail. Using this tool, the properties of the attack can be verified and different strategies for recovering coefficients can be evaluated.

Handledare: Paul Stankovski Wagner (EIT)
Examinator: Thomas Johansson (EIT)