Paper 2019/932

Related-key Differential Cryptanalysis of Full Round CRAFT

Muhammad ElSheikh and Amr M. Youssef


$\texttt{CRAFT}$ is a lightweight tweakable block cipher introduced in FSE 2019. One of the main design criteria of $\texttt{CRAFT}$ is the efficient protection of its implementations against differential fault analysis. While the authors of $\texttt{CRAFT}$ provide several cryptanalysis results in several attack models, they do not claim any security of $\texttt{CRAFT}$ against related-key differential attacks. In this paper, we utilize the simple key schedule of $\texttt{CRAFT}$ to propose a systematic method for constructing several repeatable 2-round related-key differential characteristics with probability $2^{-2}$. We then employ one of these characteristics to mount a key recovery attack on full-round $\texttt{CRAFT}$ using $2^{31}$ queries to the encryption oracle and $2^{85}$ encryptions, and $2^{41}$ 64-bit blocks of memory. Additionally, we manage to use 8 related-key differential distinguishers, with 8 related-key differences, in order to mount a key recovery attack on the full-round cipher with $2^{35.17}$ queries to the encryption oracle, $2^{32}$ encryptions and about $2^6$ 64-bit blocks of memory. Furthermore, we present another attack that recovers the whole master key with $2^{36.09}$ queries to the encryption oracle and only $11$ encryptions with $2^7$ blocks of memory using 16 related-key differential distinguishers.

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. SPACE 2019
Contact author(s)
m_elshei @ encs concordia ca
2019-11-04: revised
2019-08-18: received
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Short URL
Creative Commons Attribution


      author = {Muhammad ElSheikh and Amr M.  Youssef},
      title = {Related-key Differential Cryptanalysis of Full Round CRAFT},
      howpublished = {Cryptology ePrint Archive, Paper 2019/932},
      year = {2019},
      note = {\url{}},
      url = {}
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