### Iterative Differential Characteristic of TRIFLE-BC

Fukang Liu and Takanori Isobe

##### Abstract

TRIFLE is a Round 1 candidate of the NIST Lightweight Cryptography Standardization process. In this paper, we present an interesting 1-round iterative differential characteristic of the underlying block cipher TRIFLE-BC used in TRIFLE, which holds with probability of $2^{-3}$. Consequently, it allows to mount distinguishing attack on TRIFLE-BC for up to 43 (out of 50) rounds with data complexity $2^{124}$ and time complexity $2^{124}$. Most importantly, with such an iterative differential characteristic, the forgery attack on TRIFLE can reach up to 21 (out of 50) rounds with data complexity $2^{63}$ and time complexity $2^{63}$. Finally, to achieve key recovery attack on reduced TRIFLE, we construct a differential characteristic covering three blocks by carefully choosing the positions of the iterative differential characteristic. As a result, we can mount key-recovery attack on TRIFLE for up to 11 rounds with data complexity $2^{63}$ and time complexity $2^{104}$. Although the result in this paper cannot threaten the security margin of TRIFLE, we hope it can help further understand the security of TRIFLE.

Note: Correct some editorial mistakes.

Available format(s)
Category
Secret-key cryptography
Publication info
Published elsewhere. MINOR revision.SAC 2019
Keywords
Contact author(s)
liufukangs @ 163 com
takanori isobe @ ai u-hyogo ac jp
History
2019-07-09: revised
See all versions
Short URL
https://ia.cr/2019/727

CC BY

BibTeX

@misc{cryptoeprint:2019/727,
author = {Fukang Liu and Takanori Isobe},
title = {Iterative Differential Characteristic of TRIFLE-BC},
howpublished = {Cryptology ePrint Archive, Paper 2019/727},
year = {2019},
note = {\url{https://eprint.iacr.org/2019/727}},
url = {https://eprint.iacr.org/2019/727}
}

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