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Improved Security Bounds for Generalized Feistel Networks

Authors:
Yaobin Shen , Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
Chun Guo , Key Laboratory of Cryptologic Technology and Information Security of Ministry of Education, Shandong University, Qingdao, Shandong, 266237, China; School of Cyber Science and Technology, Shandong University, Qingdao, Shandong, China
Lei Wang , Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
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DOI: 10.13154/tosc.v2020.i1.425-457
URL: https://tosc.iacr.org/index.php/ToSC/article/view/8571
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Abstract: We revisit the security of various generalized Feistel networks. Concretely, for unbalanced, alternating, type-1, type-2, and type-3 Feistel networks built from random functions, we substantially improve the coupling analyzes of Hoang and Rogaway (CRYPTO 2010). For a tweakable blockcipher-based generalized Feistelnetwork proposed by Coron et al. (TCC 2010), we present a coupling analysis and for the first time show that with enough rounds, it achieves 2n-bit security, and this provides highly secure, double-length tweakable blockciphers.
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BibTeX
@article{tosc-2020-30280,
  title={Improved Security Bounds for Generalized Feistel Networks},
  journal={IACR Transactions on Symmetric Cryptology},
  publisher={Ruhr-Universität Bochum},
  volume={2020, Issue 1},
  pages={425-457},
  url={https://tosc.iacr.org/index.php/ToSC/article/view/8571},
  doi={10.13154/tosc.v2020.i1.425-457},
  author={Yaobin Shen and Chun Guo and Lei Wang},
  year=2020
}