Impossible Differential Cryptanalysis of Reduced-Round Tweakable TWINE

Mohamed Tolba; Muhammad ElSheikh; Amr M.  Youssef

Paper 2020/052

Impossible Differential Cryptanalysis of Reduced-Round Tweakable TWINE

Mohamed Tolba, Muhammad ElSheikh, and Amr M. Youssef

Abstract

Tweakable TWINE (T-TWINE) is a new lightweight tweakable block cipher family proposed by Sakamoto . at IWSEC 2019. T-TWINE is the first Tweakable Block Cipher (TBC) that is built on Generalized Feistel Structure (GFS). It is based on the TWINE block cipher in addition to a simple tweak scheduling based on SKINNY’s tweakey schedule. Similar to TWINE, it has two versions, namely, T-TWINE-80 and T-TWINE-128, both have a block length of 64 bits and employ keys of length 80 and 128 bits, respectively. In this paper, we present impossible differential attacks against reduced-round versions of T-TWINE-80 and T-TWINE-128. First, we present an 18-round impossible differential distinguisher against T-TWINE. Then, using this distinguisher, we attack 25 and 27 rounds of T-TWINE-80 and T-TWINE-128, respectively.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: Cryptanalysis Impossible differential attacks Tweakable Block ciphers TWINE T-TWINE
Contact author(s): m_elshei @ encs concordia ca
History: 2020-01-17: received
Short URL: https://ia.cr/2020/052
License: CC BY

BibTeX

@misc{cryptoeprint:2020/052,
      author = {Mohamed Tolba and Muhammad ElSheikh and Amr M.  Youssef},
      title = {Impossible Differential Cryptanalysis of Reduced-Round Tweakable {TWINE}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/052},
      year = {2020},
      url = {https://eprint.iacr.org/2020/052}
}