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...

Time-memory-data tradeoff (TMD-TO) attacks limit the security level of many classical stream ciphers (like E0, A5/1, Trivium, Grain) to n/2, where n denotes the inner state length of the underlying keystream generator. This implies that to withstand TMD tradeoff attacks, the state size should be at least double the key size. In 2015, Armknecht and Mikhalev introduced a new line of research, whi...

The cube attack is a powerful cryptanalytic tool for the analysis of stream ciphers, which until recently were investigated in a blackbox scenario with a minimal consideration to their internal and polynomial structures. In this paper, we analyze the lightweight stream cipher WG5, which offers 80-bit security, using cube attacks in a non-blackbox polynomial setting employing the division proper...

Most stream ciphers used in practice are vulnerable against generic collision attacks, which allow to compute the secret initial state on the basis of O(2) keystream bits in time and space O(2), where n denotes the inner state length of the underlying keystream generator. This implies the well-known rule that for reaching n-bit security, the inner state length should be at least 2n. Correspondi...

Stream ciphers are cryptographic primitives that are used to ensure the privacy of a message that is sent over a digital communication channel. In this thesis we will present new cryptanalytic results for several stream ciphers. The thesis provides a general introduction to cryptology, explains the basic concepts, gives an overview of various cryptographic primitives and discusses a number of d...

Time-memory-data (TMD) tradeoff attacks limit the security level of many classical stream ciphers (like E0, A5/1, Trivium, Grain) to 2 n, where n denotes the inner state length of the underlying keystream generator. This implies that to withstand TMD tradeoff attacks, the state size should be at least double the key size. In 2015, Armknecht and Mikhalev introduced a new line of research, which ...

Internet Of Things is an evolution and superset of current internet of networks of computers. We are already on the way of connecting every Thing to internet, mobile internet focusing on 3G phones is a good pioneer example. Our focuses are turning from devices with high capability of computing and storage to those with constrained resources (CPU, memory, energy), from reliable transportations t...

The cube attack is an important technique for the cryptanalysis of symmetric key primitives, especially for stream ciphers. Aiming at recovering some secret key bits, the adversary reconstructs a superpoly with the secret key bits involved, by summing over a set of the plaintexts/IV which is called a cube. Traditional cube attack only exploits linear/quadratic superpolies. Moreover, for a long ...

Stream ciphers are fast cryptographic primitives to provide confidentiality of electronically transmitted data. They can be very suitable in environments with restricted resources, such as mobile devices or embedded systems. Practical examples are cell phones, RFID transponders, smart cards or devices in sensor networks. Besides efficiency, security is the most important property of a stream ci...