About the Fujisaki-Okamoto Transformation in the Code-Based Algorithms of the NIST Post-quantum Call

González de la Torre, M.Á., Hernández Encinas, L.
P. García Bringas et al. (Eds.), Springer, Lecture Notes in Networks and Systems 523, 75-85, ISBN 978-3-031-18408-6, Salamanca, Septiembre, 2022

Proc. International Joint Conference 15th International Conference on Computational Intelligence in Security for Information Systems (CISIS 2022) 13th International Conference on EUropean Transnational Education (ICEUTE 2022).

Post-quantum encryption schemes use variants of the Fujisaki-Okamoto transformation in order to construct a highly secure key encapsulation mechanism from a weakly secure public key encryption scheme. In the third round of the NIST post-quantum cryptography standardization call, all the candidates for the key encapsulation mechanism category use some of these transformations. This work studies how the mentioned transformations are applied in the code-based candidates of the NIST third round. These are Classic McEliece (finalist), BIKE (alternative) and HQC (alternative). Studying the differences between the transformations gives a better understanding of these candidates.


This work was supported in part by project P2QProMeTe (PID2020-112586RB-I00/AEI/10.13039/501100011033), ORACLE Project, with reference PCI2020-120691-2, funded by MCIN/AEI/10.13039/501100011033 and European Union “NextGenerationEU/PRTR”, in part by the Spanish State Research Agency (AEI) of the Ministry of Science and Innovation (MCIN), and in part by the EU Horizon 2020 research and innovation programme, project SPIRS (Grant Agreement No. 952622).