Improved Security Bounds for Generalized Feistel Networks

Yaobin Shen; Chun Guo; Lei Wang

Paper 2020/285

Improved Security Bounds for Generalized Feistel Networks

Yaobin Shen, Chun Guo, and Lei Wang

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 Feistel network 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.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Published by the IACR in FSE 2020
Keywords: Block ciphers Coupling Tweakable block ciphers Generalized Feistel networks Provable security Mode of operation
Contact author(s): yb_shen @ sjtu edu cn
History: 2020-03-06: received
Short URL: https://ia.cr/2020/285
License: CC BY

BibTeX

@misc{cryptoeprint:2020/285,
      author = {Yaobin Shen and Chun Guo and Lei Wang},
      title = {Improved Security Bounds for Generalized Feistel Networks},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/285},
      year = {2020},
      url = {https://eprint.iacr.org/2020/285}
}