Key schedules in block ciphers are often highly simplified, which causes weakness that can be exploited in many attacks. At ASIACRYPT 2011, Dunkelman et al. proposed a technique using the weakness in the key schedule of AES, called key-bridging technique, to improve the overall complexity. The advantage of key-bridging technique is that it allows the adversary to deduce some sub-key bits from s...

TWINE is a recent lightweight block cipher based on a Feistel structure. We rst present two new attacks on TWINE-128 reduced to 25 rounds that have a slightly higher overall complexity than the 25round attack presented by Wang and Wu at ACISP 2014, but a lower data complexity. Then, we introduce alternative representations of both the round function of this block cipher and of a sequence of 4 r...

In the biclique attack, a shorter biclique usually results in less data complexity, but at the expense of more computational complexity. The early abort technique can be used in partial matching part of the biclique attack in order to slightly reduce the computations. In this paper, we make use of this technique, but instead of slight improvement in the computational complexity, we keep the amo...

Division property is a generalized integral property proposed by Todo at EUROCRYPT 2015, and very recently, Todo et al. proposed bit-based division property and applied to SIMON32 at FSE 2016. However, this technique can only be applied to block ciphers with block size no larger than 32 due to its high time and memory complexity. In this paper, we extend Mixed Integer Linear Programming (MILP) ...

Modern day lightweight block ciphers provide powerful encryption methods for securing IoT communication data. Tiny digital devices exchange private data which the individual users might not be willing to get disclosed. On other hand, adversaries try their level best capture this The first step towards is identify scheme. This work an effort construct a distinguisher cipher used in encrypting tr...

Impossible differential attacks are among the most powerful forms of cryptanalysis against block ciphers. We present in this paper an in-depth complexity analysis of these attacks. We show an unified way to mount such attacks and provide generic formulas for estimating their time and data complexities. LBlock is a well studied lightweight block cipher with respect to impossible differential att...

Ubiquitous and pervasive computing are new era of computing and it needs lightweight cryptographic algorithms for security. Lightweight cryptography is used for resource constrained devices (which have limited memory, limited power and less processing capability) such as radio frequency identification (RFID) tags, contactless smart cards, wireless sensor network, health care devices and interne...

In this paper, we reveal a fundamental property of block ciphers: There can exist linear approximations such that their biases ε are deterministically invariant under key difference. This behaviour is highly unlikely to occur in idealized ciphers but persists, for instance, in 5-round AES. Interestingly, the property of key difference invariant bias is independent of the bias value ε itself and...

In this paper we improve Wu and Wang’s method for finding impossible differentials of block cipher structures. This improvement is more general than Wu and Wang’s method that it can find more impossible differentials with less time. We apply it on GenCAST256, Misty, Gen-Skipjack, Four-Cell, Gen-MARS, SMS4, MIBS, Camellia*, LBlock, E2 and SNAKE block ciphers. All impossible differentials discove...