报告人：钟江华（中国科学院信息工程研究所）

时  间：11月11日下午16:30

地  点：腾讯会议ID：872 543 454（无密码）

内容摘要:

Many recent stream ciphers use Galois nonlinear feedback shift registers (NFSRs) as their main building blocks, such as the hardware-oriented finalists Grain and Trivium in the eSTREAM project. Previous work has found some types of Galois NFSRs equivalent to Fibonacci ones, including that used in Grain. In this talk, based on the observability of an NFSR on [0,N-1], which means any two distinct initial states of an NFSR are distinguishable from their corresponding output sequences of length N, we first give some necessary and sufficient conditions for Galois NFSRs equivalent to Fibonacci ones, covering and improving the previous work on this research. We then present some new types of Galois NFSRs equivalent to Fibonacci ones. As an application of our theoretical results, we finally reveal that the 288-stage Galois NFSR used in Trivium is neither equivalent to a 288-stage Fibonacci NFSR, nor observable on [0,287], theoretically verifying Trivium's good design criteria of confusion and diffusion.

个人简介：

钟江华，中国科学院信息工程研究所副研究员。2007年于中国科学院系统与系统科学研究院获博士学位，2007-2009年为瑞典皇家工学院博士后。一直从事非线性研究。目前主要关注密码学与系统科学的交叉学科问题，特别是流密码中的非线性问题。在IEEE Transactions on Information Theory、IEEE Transactions on Communications、 IEEE Sensors Journal、Automatica 等密码和控制领域的国际著名期刊发表论文近30篇。曾获2016年省部级科技进步奖三等奖。

联系人：祝辉林