具有最小异或数的最大距离可分矩阵的构造

Constructions of Maximal Distance Separable Matrices with Minimum XOR-counts

随着物联网等普适计算的发展,传感器、射频识别(RFID)标签等被广泛使用,这些微型设备的计算能力有限,传统的密码算法难以实现,需要硬件效率高的轻量级分组密码来支撑。最大距离可分(MDS)矩阵扩散性能最好,通常被用于构造分组密码扩散层,异或操作次数(XORs)是用来衡量扩散层硬件应用效率的一个指标。该文利用一种能更准确评估硬件效率的XORs计算方法,结合一种特殊结构的矩阵Toeplitz矩阵,构造XORs较少效率较高的MDS矩阵。利用Toeplitz矩阵的结构特点,改进矩阵元素的约束条件,降低矩阵搜索的计算复杂度,在有限域F28上得到了已知XORs最少的4×4MDS矩阵和6×6MDS矩阵,同时还得到XORs等于已知最优结果的5×5MDS矩阵。该文构造的具有最小XORs的MDS Toeplitz矩阵,对轻量级密码算法的设计具有现实意义。

With the development of the internet of things,small-scale communication devices such as wireless sensors and the Radio Frequency IDentification(RFID)tags are widely used,these micro-devices have limited computing power,so that the traditional cryptographic algorithms are difficult to implement on these devices.How to construct a high-efficiency diffusion layer becomes an urgent problem.With the best diffusion property,the Maximal Distance Separable(MDS)matrix is often used to construct the diffusion layer of block ciphers.The number of XOR operations(XORs)is an indicator of the efficiency of hardware applications.Combined with the XORs calculation method which can evaluate hardware efficiency more accurately and a matrix with special structure Toeplitz matrix,efficient MDS matrices with less XORs can be constructed.Using the structural characteristics of the Toeplitz matrix,the constraints of matrix elements are improved,and the complexity of matrices searching is reduced.The 4×4 MDS matrices and the 6×6 MDS matrices with the least XORs in the finite field F28 are obtained,and the 5×5 MDS matrices with the XORs which are equal to the known optimal results are obtained too.The proposed method of constructing MDS Toeplitz matrices with the least XORs has significance on the design of lightweight cryptographic algorithms.