Paper 2026/1039

Related-Differential Distinguishers on up to 7 Rounds of AES

Lin Tan, Information Engineering University

Wenfeng Qi, Information Engineering University

Abstract

Round-reduced variants of AES are widely used as building blocks in the design of cryptographic schemes. The study of non-random properties and distinguishers for round-reduced AES has always been an important research topic. The longest known secret-key distinguishers on AES cover 6 rounds. Related differences and related differentials were introduced by the designers of AES in 2009, but research in this direction remains limited. In this paper, we provide a new perspective on related differences through exchange and shift operations. Based on related differentials, we present new non-random properties and secret-key distinguishers for up to 7 rounds of AES. For 5-round AES, we present a new property with probability $2^{-22}$ by combining one-round byte-wise related differentials with the 4-round zero-difference property. Then we improve the secret-key distinguishers on 5-round AES in both the chosen plaintexts (CP) and adaptively chosen plaintexts (ACP) settings, achieving data/time complexities of $2^{27.2}$/$2^{28.05}$ and $2^{23.32}$/$2^{23.54}$, respectively. For 7-round AES, we identify the first non-random property by exploiting one-round exchanged diagonal related differentials and combining them with the 4-round related differentials given by Bardeh and Rijmen. Then, we propose the first secret-key distinguisher for 7-round AES with data complexity lower than the full codebook. For 6-round AES, using shifted diagonal related differentials, we present an alternative distinguisher that is dual to the exchange-attack distinguisher from ASIACRYPT 2019.

@misc{cryptoeprint:2026/1039,
      author = {Xueping Yan and Lin Tan and Wenfeng Qi},
      title = {Related-Differential Distinguishers on up to 7 Rounds of {AES}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/1039},
      year = {2026},
      url = {https://eprint.iacr.org/2026/1039}
}