Cryptology ePrint Archive: Report 2021/128

Designing Tweakable Enciphering Schemes Using Public Permutations

Debrup Chakraborty and Avijit Dutta and Samir Kundu

Abstract: A tweakable enciphering scheme (TES) is a length preserving (tweakable) encryption scheme that provides (tweakable) strong pseudorandom permutation security on arbitrarily long messages. TES is traditionally built using block ciphers and the security of the mode depends on the strong pseudorandom permutation security of the underlying block cipher. In this paper, we construct TESs using public random permutations. Public random permutations are being considered as a replacement of block cipher in several cryptographic schemes including AEs, MACs, etc. However, to our knowledge, a systematic study of constructing TES using public random permutations is missing. In this paper, we give a generic construction of a TES which uses a public random permutation, a length expanding public permutation based PRF and a hash function which is both almost xor universal and almost regular. Further, we propose a concrete length expanding public permutation based PRF construction. We also propose a single keyed TES using a public random permutation and an AXU and almost regular hash function.

Category / Keywords: secret-key cryptography / Tweakable Enciphering Scheme, HCTR, Public Permutation.

Date: received 5 Feb 2021, last revised 19 Apr 2021

Contact author: samirkundu3 at gmail com, debrup@isical ac in, avirocks dutta13@gmail com

Available format(s): PDF | BibTeX Citation

Version: 20210420:041433 (All versions of this report)

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