Authors:
Kaiyan Zheng
and
Peng Wang
Affiliation:
Institute of Information Engineering, Chinese Academy of Sciences and University of Chinese Academy of Sciences, China
Keyword(s):
Encryption Scheme, Blockwise Adaptive Attack, Related-key Attack, Even-Mansour.
Abstract:
In this paper we discuss how to construct encryption schemes from permutations. Firstly we discuss an intuitive
way to design permutation-based encryption schemes, that is by combining mainstream blockcipherbased
encryption modes (such as CBC, OFB, CFB, CTR) with the Even-Mansour cipher, which is an elegant
permutation-based blockcipher. Unfortunately, most of encryption schemes produced by the combination
strategy are not secure enough. Then we propose 4 permutation-based encryption schemes - PCBC, POFB,
PCFB and PCTR, which can resist both the blockwise adaptive attack and the F-related-key attack when
using a non-repeated nonce. To illustrate it, we give a definition of the indistinguishability from random bits
against blockwise adaptive chosen plaintext attack in the F-related-key setting, and then prove the security
of PCBC in such definition. The other 3 schemes have similar results. Constructing from a single permutation,
these 4 encryption schemes are practical, in the sens
e that they are less prone to misuse, bring less pressure
on the key-management in real world, and apply to blockwise adaptive scenarios including real-time applications,
on-line settings, memory-restricted devices, etc. Moreover they are more efficient than the Sponge
construction.
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