Abstract BORON is a lightweight substitution–permutation network cipher proposed in 2017. We reduce the number of guessed key bits by key-bridging technology and first utilize Fast Walsh Transform on BORON to minimize the time complexity. Finally, this paper gives the better key-recovery attack against block cipher BORON than previously proposed by 2 rounds: we realize a 11-round key-recovery attack on BORON-80 and 13-round key-recovery attack on BORON-128. The attacks proposed in this paper are the best attacks against BORON-80/128 to date.

As the Internet of Things (IoT) continues to grow, the urgency to bolster IoT device security escalates, particularly in evaluating the security of lightweight ciphers. Since the inception of Keccak (also known as SHA-3), embedding a permutation within a certain operational mode has become a pivotal approach in designing lightweight cryptography. This led to numerous permutation-based lightweight ciphers tailored for IoT applications. Among them, Xoodyak and Gaston are typical examples and even incorporate Keccak’s nonlinear operation$\chi $within their round functions. This article focuses on assessing the security of Keccak-like lightweight hash functions against preimage attacks. We introduce a generic preimage attack framework from an algebraic perspective and propose a new linearization method that leverages the algebraic properties of$\chi $in the permutation. Additionally, in order to find good guessing strategies, we develop automatic tools based on bit-level mixed-integer linear programming on Xoodyak and Gaston. As a result, the complexity of finding a preimage for 2-round Xoodyak-XOF with a 128-bit digest is$2^{94.66}$while that for 3-round Xoodyak-XOF can be reduced from$2^{125.06}$to$2^{123.91}$and memory consumption from$2^{97}$to a negligible level. This marks the most efficient preimage attack against a 3-round Xoodyak-XOF to date. Furthermore, we present the first preimage attacks on 1-/2-round Gaston with complexities of$2^{90.56}$and$2^{122.15}$, respectively.

Abstract Demirci–Selçuk meet-in-the-middle (DS-MITM) attack is an effective method for cryptanalysis. As far as we know, the published automatic results of DS-MITM attack are all for byte-oriented ciphers. In this article, we first propose the automatic analysis method of DS-MITM attack for bit-oriented ciphers based on constraint programming, which is integrated with key-bridging technique. Based on the automatic modeling method, we propose the first result of DS-MITM attack on SIMON, which is a family of lightweight block ciphers proposed by the National Security Agency (NSA) in 2013.