This paper presents differential attacks on Simon and Speck, two families of lightweight block ciphers that were presented by the U.S. National Security Agency in June 2013. We describe attacks on up to slightly more than half the number of rounds. While our analysis is only of academic interest, it demonstrates the drawback of the intensive optimizations in Simon and Speck.

Simon and Speck are families of lightweight block ciphers proposed in June 2013 by the US National Security Agency. Here we discuss ASIC implementations of these algorithms, presenting in some detail how one implements the smallest bit-serial versions of the algorithms. We also give area and throughput results for a variety of implementations—bit serial, iterated, and partially and fully pipeli...

The last several years have witnessed a surge of activity in lightweight cryptographic design. Many lightweight block ciphers have been proposed, targeted mostly at hardware applications. Typically software performance has not been a priority, and consequently software performance for many of these algorithms is unexceptional. Simon and Speck are lightweight block cipher families developed by t...

Simon and Speck are families of lightweight block ciphers designed by the U.S. National Security Agency and published in 2013. Each of the families contains 10 variants, supporting a wide range of block and key sizes. Since the publication of Simon and Speck, several research papers analyzed their security using various cryptanalytic techniques. The best previously published attacks on all the ...

SIMON and SPECK family ciphers have attracted the attention of cryptographers all over the world since proposed by NSA in June, 2013. At CHES 2015, Simeck, a new block cipher inspired from both SIMON and SPECK is proposed, which is more compact and efficient. However, the security evaluation on Simeck against zero correlation linear cryptanalysis seems missing from the specification. The main f...

In this paper, we examine the validity of differential characteristics ARX-based block ciphers. Recently, it was shown that some ciphers, SKINNY and GIFT, in literature are not valid [1]. However, their work is limited to SPN-based We find out SIMON, SPECK, CHAM, appeared valid. Our indicates only but also ciphers may be invalid.

In June 2013 the U.S. National Security Agency proposed two families of ultra-lightweight block ciphers, called Simon and Speck. In this paper we present the first cryptanalysis of round-reduced versions of Simon. We mount differential distinguishers and key-recovery attacks on up to 14/32, 17/36, 21/44, 26/54, and 32/72 rounds, for the 32-, 48-, 64-, 96-, and 128-bit versions, respectively. Fu...

In this paper we continue the previous line of research on the analysis of the differential properties of the lightweight block ciphers Simon and Speck. We apply a recently proposed technique for automatic search for differential trails in ARX ciphers and improve the trails in Simon32 and Simon48 previously reported as best. We further extend the search technique for the case of differentials a...