Differential Cryptanalysis of Round-Reduced Sparx-64/128

  • Ralph Ankele
  • Eik List
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10892)


Sparx is a family of ARX-based block ciphers designed according to the long-trail strategy (LTS) that were both introduced by Dinu et al. at ASIACRYPT’16. Similar to the wide-trail strategy, the LTS allows provable upper bounds on the length of differential characteristics and linear paths. Thus, the cipher is a highly interesting target for third-party cryptanalysis. However, the only third-party cryptanalysis on Sparx-64/128 to date was given by Abdelkhalek et al. at AFRICACRYPT’17 who proposed impossible-differential attacks on 15 and 16 (out of 24) rounds.

In this paper, we present chosen-ciphertext differential attacks on 16 rounds of Sparx-64/128. First, we show a truncated-differential analysis that requires \(2^{32}\) chosen ciphertexts and approximately \(2^{93}\) encryptions. Second, we illustrate the effectiveness of boomerangs on Sparx by a rectangle attack that requires approximately \(2^{59.6}\) chosen ciphertexts and about \(2^{122.2}\) encryption equivalents. Finally, we also considered a yoyo attack on 16 rounds that, however, requires the full codebook and approximately \(2^{126}\) encryption equivalents.


Symmetric-key cryptography Cryptanalysis Boomerang Truncated differential Yoyo ARX 


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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Royal Holloway University of LondonEghamUK
  2. 2.Bauhaus-Universität WeimarWeimarGermany

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