Loiss is a byte-oriented stream cipher designed by Dengguo Feng et al. Its design builds upon the design of the SNOW family of ciphers. The algorithm consists of a linear feedback shift register (LFSR) and a non-linear finite state machine (FSM). Loiss utilizes a structure called Byte-Oriented Mixer with Memory (BOMM) in its filter generator, which aims to improve resistance against algebraic a...

The power of a statistical attack is inversely proportional to the number of plaintexts needed to recover information on the encryption key. By analyzing the distribution of the random variables involved in the attack, cryptographers aim to provide a good estimate of the data complexity of the attack. In this paper, we analyze the hypotheses made in simple, multiple, and multidimensional linear...

By considering the role of non-linear approximations in linear cryptanalysis we obtain a generalization of Matsui’s linear cryptanalytic techniques. This approach allows the cryptanalyst greater flexibility in mounting a linear cryptanalytic attack and we demonstrate the effectiveness of our non-linear techniques with some simple attacks on LOKI91. These attacks potentially allow for the recove...

In 2013, Borghoff et al. introduced a slender-set linear cryptanalysis on PRESENT-like ciphers with key-dependent secret S-boxes. In this paper, we propose an improved slender-set linear attack to PRESENTlike ciphers with secret S-boxes. We investigate three new cryptanalytic techniques, and use them to recover the secret S-boxes efficiently. Our first new idea is that we propose a new techniqu...

NLS is one of the stream ciphers submitted to the eSTREAM project. We present a distinguishing attack on NLS by Crossword Puzzle (CP) attack method which is newly introduced in this paper. We build the distinguisher by using linear approximations of both the non-linear feedback shift register (NFSR) and the nonlinear filter function (NLF). Since the bias of the distinguisher depends on the Kons...

The 32-bit MAC of Grain-128a is a linear combination of the first 64 and then the alternative keystream bits. In this paper we describe a successful differential fault attack on Grain-128a, in which we recover the secret key by observing the correct and faulty MACs of certain chosen messages. The attack works due to certain properties of the Boolean functions and corresponding choices of the ta...

At the RFID Security Workshop 2007, Adi Shamir presented a new challenge-response protocol well suited for RFIDs, although based on the Rabin public-key cryptosystem. This protocol, which we call SQUASH-0, was using a linear mixing function which was subsequently withdrawn. Essentially, we mount an attack against SQUASH-0 with full window which could be used as a “known random coins attack” aga...

The block cipher MISTY1 [9] proposed for the NESSIE project [11] is a Feistel network augmented with key-dependent linear FL functions. The proposal allows a variable number of rounds provided that it is a multiple of four. Here we present a new attack – the Slicing Attack – on the 4-round version, which makes use of the special structure and position of these key-dependent linear FL functions....

This paper presents differential attacks of round-reduced versions of Simon with up to 18/32, 19/36, 25/44, 35/54, and 46/72 rounds for the 32-, 48-, 64-, 96-, and 128-bit versions, respectively. Furthermore, we consider in brief related-key rectangle, impossible-differential, and also linear attacks. While all our attacks are completely academic, they demonstrate the drawback of the intensive ...

In 1985 Siegenthaler introduced the concept of correlation attacks on LFSR based stream ciphers. A few years later Meier and Staffelbach demonstrated a special technique, usually referred to as fast correlation attacks, that is very effective if the feedback polynomial has a special form, namely, if its weight is very low. Due to this seminal result, it is a well known fact that one avoids low ...