AES is arguably the most widely used cipher.  This talk covers a recent line of works targeting *provable* security of AES and other block ciphers.

We consider *t-wise independence*, a natural and attractive security target for block ciphers.  A block cipher is t-wise independent, if for any t plaintexts, the joint distribution of the t corresponding ciphertexts is statistically close to uniform.  It implies resistance to any statistical attack that only involves a few inputs.

We have a collection of results showing AES and a few of its variants are t-wise independent, under different parameters (the value of t, the security level, the number of rounds, etc).  Some of them will be presented in this talk.

Ref:

The t-wise Independence of Substitution-Permutation Networks. Tianren Liu, Stefano Tessaro, Vinod Vaikuntanathan.  Crypto 2019.   https://eprint.iacr.org/2021/507

Layout Graphs, Random Walks and the t-wise Independence of SPN Block Ciphers.  Tianren Liu, Angelos Pelecanos, Stefano Tessaro, Vinod Vaikuntanathan.  Crypto 2023.

Tianren Liu is an assistant professor in Peking University.  He received bachelor and Phd degrees from Tsinghua University and MIT respectively, and was a postdoc researcher in UW.  His main research interest is on cryptorgraphy.  Most of his works have a strong information-theoretic flavor.