Provable security against generic attacks on stream ciphers

On Stream Ciphers with Provable Beyond-the-Birthday-Bound Security against Time-Memory-Data Tradeoff Attacks

We propose and analyze the Lizard-construction, a way to construct keystream generator (KSG) based stream ciphers with provable 2 3 n-security with respect to generic time-memory-data tradeoff attacks. Note that for the vast majority of known practical KSG-based stream ciphers such attacks reduce the effective key length to the birthday bound n/2, where n denotes the inner state length of the u...

On the Applicability of Distinguishing Attacks Against Stream Ciphers

We demonstrate that the existence of distinguishing attacks against stream ciphers is unrelated to their security in practical use, and in particular that the amount of data required to perform a distinguishing attack is unrelated to the key length of the cipher. The implication for the NESSIE Project is that no submitted symmetric cipher would be accepted under the unpublished rules for distin...

Generic Attacks on Symmetric Ciphers

Key differentiation attacks on stream ciphers

In this paper the applicability of differential cryptanalytic tool to stream ciphers is elaborated using the algebraic representation similar to early Shannon’s postulates regarding the concept of confusion. In 2007, Biham and Dunkelman [3] have formally introduced the concept of differential cryptanalysis in stream ciphers by addressing the three different scenarios of interest. Here we mainly...

Linearisation Attacks on FCSR-based Stream Ciphers

This paper presents a new class of cryptanalytic attacks, which are applicable against those binary additive synchronous stream ciphers, whose analysis theory is based on the properties of 2-adic numbers. These attacks are named as ‘Linearisation Attacks’. Linearisation attacks consist of three variants, which are referred as ‘Conventional Linearisation Attacks (CLAs)’, ‘Fast Linearisation Atta...