The Cube Attack on Stream Cipher Trivium and Quadraticity Tests

Issue title: Cryptology in Progress: 10th Central European Conference on Cryptology, Będlewo Poland, 2010

Article type: Research Article

Authors: Mroczkowski, Piotr | Szmidt, Janusz

Affiliations: Department of Cryptology, Military Communication Institute, ul. Warszawska 22A, 05-130 Zegrze, Poland. [email protected]; [email protected]

Note: [] Address for correspondence: Department of Cryptology, Military Communication Institute, ul. Warszawska 22A, 05-130 Zegrze, Poland

Abstract: In 2008 I. Dinur and A. Shamir presented a new type of algebraic attack on symmetric ciphers named cube attack. The method has been applied to reduced variants of stream ciphers Trivium and Grain-128, reduced variants of the block ciphers Serpent and CTC and to a reduced version of the keyed hash function MD6. Previously, a very similar attack named AIDA was introduced by M. Vielhaber, in 2007. In this paper we develop quadraticity tests within the cube attack and apply them to a variant of stream cipher Trivium reduced to 709 initialization rounds. Using this method we obtain the full 80-bit secret key. In this way it eliminates the stage of brute force search of some secret key bits which occured in previous cube attacks.

DOI: 10.3233/FI-2012-631

Journal: Fundamenta Informaticae, vol. 114, no. 3-4, pp. 309-318, 2012