New Integral Distinguishers and Security Reassessment of LTLBC

Abhilash Kumar Das

2025

Abstract

This paper presents an in-depth study of integral distinguishers for the LTLBC block cipher, a 14-round 64-bit lightweight cryptographic scheme designed for low-latency applications in IoT environments. Leveraging the division property technique introduced by Yosuke Todo, we employ a Mixed Integer Linear Programming (MILP) approach to identify previously unpublished 6-round integral distinguishers for LTLBC. Additionally, we studied the MixWord permutation phase and showed that the cyclic intermixing tweak to the input word doesn’t yield any significant improvement. Instead, it reduces to the original MixWord operation. This observation is rigorously justified through an algebraic proof and further followed by linear and differential cryptanalysis, leading to a revised active Sbox count for LTLBC. As a side contribution, we correct inaccuracies in the reported division property propagations for the FUTURE Sbox, initially presented at AFRICACRYPT 2022. Our findings provide a deeper understanding of LTLBC’s security and offer valuable insights for the design of future lightweight block ciphers.

Paper Citation

in Harvard Style

Das A. (2025). New Integral Distinguishers and Security Reassessment of LTLBC. In Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT; ISBN 978-989-758-760-3, SciTePress, pages 717-722. DOI: 10.5220/0013566600003979

in Bibtex Style

@conference{secrypt25,
author={Abhilash Das},
title={New Integral Distinguishers and Security Reassessment of LTLBC},
booktitle={Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT},
year={2025},
pages={717-722},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013566600003979},
isbn={978-989-758-760-3},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT
TI - New Integral Distinguishers and Security Reassessment of LTLBC
SN - 978-989-758-760-3
AU - Das A.
PY - 2025
SP - 717
EP - 722
DO - 10.5220/0013566600003979
PB - SciTePress