Combining Partial Sums and FFT for the Fastest Known Attack on 6‑Round AES

Title of the Talk: M Combining Partial Sums and FFT for the Fastest Known Attack on 6‑Round AES
Speakers: Dr. Shibam Ghosh
Host Faculty: Dr.M V Panduranga Rao
Date: Dec 22, 2025
Time: 10:30 pm.
Venue: CS-105

Abstract: The partial-sums technique introduced by Ferguson et al. (2000) achieved a 6‑round AES attack with time complexity 2^{52} S‑box evaluations, a benchmark that has stood since 2000. In 2014, Todo and Aoki proposed a comparable approach based on the Fast Fourier Transform (FFT). In this talk, I will show how to combine partial sums with FFT to get “the best of both worlds”. The resulting attack on 6‑round AES has a complexity of about 2^{46.4} additions, and I will outline how to implement it efficiently. A proof-of-concept implementation achieves a speedup of more than 32x over the previous best result, setting a new practical record for 6‑round AES after nearly 25 years.

Meeting link: https://meet.google.com/nao-jdrp-iae?hs=224