Improved Differential Analysis of Block Cipher PRIDE

In CRYPTO 2014 Albrecht \emph{et al.} brought in a 20-round iterative lightweight block cipher PRIDE which is based on a good linear layer for achieving a tradeoff between security and efficiency. A recent analysis is presented by Zhao \emph{et al.}. Inspired by their work, we use an automatic search method to find out 56 iterative differential characteristics of PRIDE, containing 24 1-round iterative characteristics, based on three of them we construct a 15-round differential and perform a differential attack on the 19-round PRIDE, with data, time and memory complexity of $2^{62}$, $2^{63}$ and $2^{71}$ respectively

RoadRunneR: A Small And Fast Bitslice Block Cipher For Low Cost 8-bit Processors

Designing block ciphers targeting resource constrained 8-bit CPUs is a challenging problem. There are many recent lightweight ciphers designed for better performance in hardware. On the other hand, most software efficient lightweight ciphers either lack a security proof or have a low security margin. To fill the gap, we present RoadRunneR which is an efficient block cipher in 8-bit software, and its security is provable against differential and linear attacks. RoadRunneR has lowest code size in Atmel’s ATtiny45, except NSA’s design SPECK, which has no security proof. Moreover, we propose a new metric for the fair comparison of block ciphers. This metric, called ST/A, is the first metric to use key length as a parameter to rank ciphers of different key length in a fair way. By using ST/A and other metrics in the literature, we show that RoadRunneR is competitive among existing ciphers on ATtiny45