蓝牙组合生成器相关系数的计算方法

Computing Correlation Coefficients of Bluetooth Combiner

蓝牙组合生成器是蓝牙协议巾使用的密钥流生成算法,它是一个带4 bit记忆的非线性组合生成器,其输入和输出之间相关系数的表示和计算是一个困难的问题,而这是对这种生成器进行相关性分析和相关攻击的基础。该文对一般的带记忆组合生成器给出了相关系数和条件相关系数的计算公式,该公式易于实现快速计算。基于此公式计算了蓝牙组合生成器的各种相关系数,并列出了部分结果。

The bluetooth combiner, a combiner with four bit memory, is the stream cipher used in bluetooth protocols. The expression and computation of correlation coefficients between inputs and outputs of this combiner is difficult, while this is the base of correlation analysis and correlation attack to it. In this paper, the formulas for correlation coefficients and conditional correlation coefficients of general combiners with memory are presented, with which the coefficients can be computed fast. By using these formulas, all kinds of correlation coefficients ofbluetooth combiner are computed, and some results are list in the paper.