In eSTREAM project, a few lightweight stream cipher for hardware was introduced (2008) and then in FSE 2015 Sprout was proposed. Sprout introduced a new idea, design of stream cipher with shorter internal state by using key not only in initialization but also in keystream generation, but it was insecure. Grain-v1 is almost the lightest secure cipher in world. Fruit stream cipher is successor of...

Linear Consistency Test (LCT) is a well-known algebraic method of cryptanalysis of stream ciphers. In this paper, we use LCT in an attack on a noised irregularly clocked linear feedback shift register (LFSR). We show that it is possible to reconstruct the initial states of both the clocked and the clocking LFSR in this scheme by using an essentially algebraic attack method, such as LCT, as a bu...

Serpent is an SP Network block cipher submitted to the AES competition and chosen as one of its five finalists. The security of Serpent is widely acknowledged, especially as the best known attack so far is a differential-linear attack on only 11 rounds out of the 32 rounds of the cipher. In this paper we introduce a more accurate analysis of the differentiallinear attack on 11-round Serpent. Th...

WG and LEX are two stream ciphers submitted to eStream – the ECRYPT stream cipher project. In this paper, we point out security flaws in the resynchronization of these two ciphers. The resynchronization of WG is vulnerable to a differential attack. For WG with 80-bit key and 80-bit IV, 48 bits of the secret key can be recovered with about 2 chosen IVs . For each chosen IV, only the first four k...

The goal of cryptography is to make it impossible to take a cipher and reproduce the original plain text without the corresponding key. With good cryptography, your messages are encrypted in such a way that brute force attacks against the algorithm or the key are all but impossible. Good cryptography gets its security by using incredibly long keys and using encryption algorithms that are resist...

In this paper, we show several known-plaintext attacks on the stream cipher HBB which was proposed recently at INDOCRYPT 2003. The cipher can operate either as a classical stream cipher in the “B mode” or as an asynchronous stream cipher in the “SS mode”. In the case of the SS mode, we present known-plaintext attacks recovering 128-bit key with the complexity 2 and 256-bit key with the complexi...

Recently, Pareek et al. proposed a symmetric key block cipher using multiple onedimensional chaotic maps. This paper reports some new findings on the security problems of this kind of chaotic cipher: 1) a number of weak keys exists; 2) some important intermediate data of the cipher are not sufficiently random; 3) the whole secret key can be broken by a known-plaintext attack with only 120 conse...

TWIS is a 128-bit lightweight block cipher that is proposed by Ojha et al. In this work, we analyze the security of the cipher against differential, impossible differential and linear attacks. For the differential case, we mount a full-round attack on TWIS and recover 12 bits of the 32-bit final subkey with 2 complexity. For the other cases, we present distinguishers which can be extended to ke...

We revisit meet-in-the-middle attacks on block ciphers and recent developments in meet-in-the-middle preimage attacks on hash functions. Despite the presence of a secret key in the block cipher case, we identify techniques that can also be mounted on block ciphers, thus allowing us to improve the cryptanalysis of the block cipher KTANTAN family. The first and major contribution is that we spot ...