International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Parallelizing the Camellia and SMS4 Block Ciphers - Extended version

Huihui Yap
Khoongming Khoo
Axel Poschmann
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Abstract: The n-cell GF-NLFSR (Generalized Feistel-NonLinear Feedback Shift Register) structure [8] is a generalized unbalanced Feistel network that can be considered as a generalization of the outer function FO of the KASUMI block cipher. An advantage of this cipher over other n-cell generalized Feistel networks, e.g. SMS4 [11] and Camellia [5], is that it is parallelizable for up to n rounds. In hardware implementations, the benefits translate to speeding up encryption by up to n times while consuming similar area and significantly less power. At the same time n-cell GF-NLFSR structures offer similar proofs of security against differential cryptanalysis as conventional n-cell Feistel structures. We also ensure that parallelized versions of Camellia and SMS4 are resistant against other block cipher attacks such as linear, boomerang, integral, impossible differential, higher order differential,interpolation, slide, XSL and related-key differential attacks.
  title={Parallelizing the Camellia and SMS4 Block Ciphers - Extended version},
  booktitle={IACR Eprint archive},
  keywords={secret-key cryptography / Generalized Unbalanced Feistel Network, GF-NLFSR, Camellia, SMS4},
  note={Extended version of paper in Africacrypt 2010 14824 received 1 Aug 2010, last revised 2 Aug 2010},
  author={Huihui Yap and Khoongming Khoo and Axel Poschmann},