[Resource Topic] 2015/182: Tweakable Blockciphers with Asymptotically Optimal Security

Welcome to the resource topic for 2015/182

Title:
Tweakable Blockciphers with Asymptotically Optimal Security

Authors: Rodolphe Lampe, Yannick Seurin

Abstract:

We consider tweakable blockciphers with beyond the birthday bound security. Landecker, Shrimpton, and Terashima (CRYPTO 2012) gave the first construction with security up to \mathcal{O}(2^{2n/3}) adversarial queries (n denotes the block size in bits of the underlying blockcipher), and for which changing the tweak does not require changing the keys for blockcipher calls. In this paper, we extend this construction, which consists of two rounds of a previous proposal by Liskov, Rivest, and Wagner (CRYPTO 2002), by considering larger numbers of rounds r>2. We show that asymptotically, as r increases, the resulting tweakable blockcipher approaches security up to the information bound, namely \mathcal{O}(2^n) queries. Our analysis makes use of a coupling argument, and carries some similarities with the analysis of the iterated Even-Mansour cipher by Lampe, Patarin, and Seurin (ASIACRYPT 2012).

ePrint: https://eprint.iacr.org/2015/182

Talk: https://www.youtube.com/watch?v=UJrr7Szm7IY

Slides: https://iacr.org/cryptodb/archive/2013/FSE/presentation/25055.pdf

See all topics related to this paper.

Feel free to post resources that are related to this paper below.

Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.

For more information, see the rules for Resource Topics .