TY - JOUR AU - Yang, Jing AU - Johansson, Thomas AU - Maximov, Alexander PY - 2020/05/07 Y2 - 2024/03/28 TI - Spectral analysis of ZUC-256 JF - IACR Transactions on Symmetric Cryptology JA - ToSC VL - 2020 IS - 1 SE - Articles DO - 10.13154/tosc.v2020.i1.266-288 UR - https://tosc.iacr.org/index.php/ToSC/article/view/8565 SP - 266-288 AB - <p>In this paper we develop a number of generic techniques and algorithms in spectral analysis of large linear approximations for use in cryptanalysis. We apply the developed tools for cryptanalysis of ZUC-256 and give a distinguishing attack with complexity around 2<sup>236</sup>. Although the attack is only 2<sup>20</sup> times faster than exhaustive key search, the result indicates that ZUC-256 does not provide a source with full 256-bit entropy in the generated keystream, which would be expected from a 256-bit key. To the best of our knowledge, this is the first known academic attack on full ZUC-256 with a computational complexity that is below exhaustive key search.</p> ER -