Practical Collision Attacks on 22- and 23-Step SM3 (Preliminary Version)

Sitong Yuan; Haorui Cui; Hongbo Yu

Paper 2026/2700

Practical Collision Attacks on 22- and 23-Step SM3 (Preliminary Version)

Sitong Yuan

, Tsinghua University, Beijing 100084, China

Haorui Cui, Tsinghua University, Beijing 100084, China

Hongbo Yu, Tsinghua University, Beijing 100084, China

Abstract

SM3 is a 256-bit cryptographic hash function specified in the Chinese national standard GB/T 32905-2016 and the international standard ISO/IEC 10118-3:2018. In this paper, we present practical collisions for 22- and 23-step SM3 with the standard initial value. Compared with the 20-step collision result of Mendel et al. (2013), our constructions cover two and three additional steps, respectively. The time complexities are approximately \(2^{52.4}\) and \(2^{54.5}\) evaluations of 22- and 23-step SM3, respectively. We also present a semi-free-start collision for 24-step SM3.

Metadata

Available format(s): PDF
Category: Attacks and cryptanalysis
Publication info: Preprint.
Keywords: SM3 collisions semi-free-start collisions
Contact author(s): yuanst23 @ mails tsinghua edu cn
cuihr26 @ mails tsinghua edu cn
yuhongbo @ mail tsinghua edu cn
History: 2026-11-04: approved; 2026-10-30: received; See all versions
Short URL: https://ia.cr/2026/2700
License: CC BY

BibTeX

@misc{cryptoeprint:2026/2700,
      author = {Sitong Yuan and Haorui Cui and Hongbo Yu},
      title = {Practical Collision Attacks on 22- and 23-Step {SM3} (Preliminary Version)},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/2700},
      year = {2026},
      url = {https://eprint.iacr.org/2026/2700}
}