分组密码中线性映射硬件的优化设计

目前对分组密码安全性的研究主要集中在对换字盒混淆能力的研究方面,而有关换位盒扩散能力的研究文献则相对较少.利用最大距离可分映射描述了换位盒的扩散能力,给出了基于最大距离可分映射的换位盒的硬件实现方法,并对其进行了优化.对该种换位盒的空间复杂度和时间复杂度分别用硬件中异或门的数目和比特流穿越异或门的层数加以了度量.在此基础上,借助于对比特级并行乘法器的复杂度的分析,给出了一个优化最大距离可分码的算法.与以往的方法比,该算法有较低的复杂度.

Optimization design of linear mapping component in block cipher

The studies on the security of block ciphers focus on the confusion ability of substitution boxes(S-boxes),while a little research in the diffusion ability of permutation boxes(P-boxes) is made.The diffusion ability of P-boxes is described by maximum distance separable(MDS) mapping,the hardware implementation of P-boxes is presented and it is optimized.The space complexity and the time complexity of the P-boxes are measured by the number of exclusive-OR gates in the hardware and the layer number of bit stream passing through exclusive-OR gates separately.Based on these,an algorithm to optimize MDS codes is introduced by analyzing the complexity of bit parallel multipliers.The complexity of algorithm is lower than that of other algorithms.