Improved Security Bounds for Generalized Feistel Networks

IACR Transactions on Symmetric Cryptology

Lei Wang¹  Yaobin Shen²  Chun Guo³ 

[1] School of Cyber Science and Technology, Shandong University, Qingdao, Shandong, China;Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China;Key Laboratory of Cryptologic Technology and Information Security of Ministry of Education, Shandong University, Qingdao, Shandong, 266237, China;

关键词: Block ciphers;    Coupling;    Tweakable block ciphers;    Generalized Feistel networks;    Provable security;    Mode of operation;   

DOI  :  10.13154/tosc.v2020.i1.425-457

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown