Designing Full-Rate Sponge Based AEAD Modes

Authors

Bishwajit Chakraborty, Indian Statistical Institute, Kolkata
Nilanjan Datta, Institute for Advancing Intelligence
Mridul Nandi, Indian Statistical Institute, Kolkata

Document Type

Conference Article

Publication Title

Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics

Abstract

Sponge based constructions have gained significant popularity for designing lightweight authenticated encryption modes. Most of the authenticated ciphers following the Sponge paradigm can be viewed as variations of the Transform-then-permute construction. It is known that a construction following the Transform-then-permute paradigm provides security against any adversary having data complexity D and time complexity T as long as DT≪2^b-r. Here, b represents the size of the underlying permutation, while r pertains to the rate at which the message is injected. The above result demonstrates that an increase in the rate leads to a degradation in the security of the constructions, with no security guaranteed to constructions operating at the full rate, where r=b. This present study delves into the exploration of whether adding some auxiliary states could potentially improve the security of the Transform-then-permute construction. Our investigation yields an affirmative response, demonstrating that a special class of full rate Transform-then-permute with additional states, dubbed frTtP+, can indeed attain security when operated under a suitable feedback function and properly initialized additional state. To be precise, we prove that frTtP+ provides security as long as D≪2^s/2 and T≪2^s, where s denotes the size of the auxiliary state in terms of bits. To demonstrate the applicability of this result, we show that the construction ORANGE-ZESTmod belongs to this class, thereby obtaining the desired security. In addition, we propose a family of full rate Transform-then-permute construction with Beetle like feedback function, dubbed fr-Beetle, which also achieves the same level of security.

First Page

89

Last Page

110

DOI

10.1007/978-3-031-56232-7_5

Publication Date

1-1-2024

Recommended Citation

Chakraborty, Bishwajit; Datta, Nilanjan; and Nandi, Mridul, "Designing Full-Rate Sponge Based AEAD Modes" (2024). Conference Articles. 847.
https://digitalcommons.isical.ac.in/conf-articles/847