Paper Info
Title
Weak Tweak-Keys for the CRAFT Block Cipher
Abstract
CRAFT is a lightweight tweakable Substitution-Permutation-Network (SPN) block cipher optimized for efficient protection of its implementations against Differential Fault Analysis (DFA) attacks. In this paper, we present an equivalent description of CRAFT up to a simple mapping on the plaintext, ciphertext and round tweakeys. We show that the new representation, for a sub-class of keys, leads to a new structure which is a Feistel network, with non-linear operation and key addition only on half the state. Consequently, it reveals a class of weak keys for which CRAFT is less resistant against differential and linear cryptanalyses. As a result, we present one weak-key single-tweak differential attack on 23 rounds (with time complexity of 2(94) encryptions and data complexity of 2(74) chosen plaintext/tweak/ciphertext tuples and works for 2(112) weak keys) and one weak-key related-tweak attack on 26 rounds of the cipher (with time complexity of 2(105) encryptions and data complexity 2(73) chosen plaintext/tweak/ciphertext tuples and works for 2(108) weak keys). Note that these attacks do not break the security claim of the CRAFT block cipher.
Year
DOI
Venue
2022
10.46586/tosc.v2022.i1.38-63
IACR TRANSACTIONS ON SYMMETRIC CRYPTOLOGY
Keywords
DocType
Volume
CRAFT, partial key addition, partial non-linear layer
Journal
2022
Issue
ISSN
Citations 
1
2519-173X
0
PageRank 
References 
Authors
0.34
0
2
Name
Order
Citations
PageRank
Gregor Leander1128777.03
Shahram Rasoolzadeh200.68