MILP-aided Cryptanalysis of Round Reduced ChaCha

Najwa Aaraj; Florian Caullery; Marc Manzano

Paper 2017/1163

MILP-aided Cryptanalysis of Round Reduced ChaCha

Najwa Aaraj, Florian Caullery, and Marc Manzano

Abstract

The inclusion of ChaCha20 and Poly1305 into the list of supported ciphers in TLS 1.3 necessitates a security evaluation of those ciphers with all the state-of-the-art tools and innovative cryptanalysis methodologies. Mixed Integer Linear Programming (MILP) has been successfully applied to find more accurate characteristics of several ciphers such as SIMON and SPECK. In our research, we use MILP-aided cryptanalysis to search for differential characteristics, linear approximations and integral properties of ChaCha. We are able to find differential trails up to 2 rounds and linear trails up to 1 round. However, no integral distinguisher has been found, even for 1 round.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Published elsewhere. NISK 2017
Keywords: cryptanalysis stream ciphers ARX
Contact author(s): manzanomarc @ gmail com
History: 2017-11-30: received
Short URL: https://ia.cr/2017/1163
License: CC BY

BibTeX

@misc{cryptoeprint:2017/1163,
      author = {Najwa Aaraj and Florian Caullery and Marc Manzano},
      title = {{MILP}-aided Cryptanalysis of Round Reduced {ChaCha}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2017/1163},
      year = {2017},
      url = {https://eprint.iacr.org/2017/1163}
}