中文摘要：

密钥产生器是流密码系统的核心部件，根据非线性组合流密钥生成器的构造思想，本文提出了一种新的RSA—LFSR密钥流产生器，该产生器将RSA与LFSR算法相结合所产生的随机序列用一种基于基因表达式程序设计（GEP）的演化布尔函数进行组合运算输出密钥流；并对此产生器生成的不同长度密钥序列进行安全性检验．通过游程检验、频数检验、序列测试和线性复杂度计算的实验证明，使用基于GEP演化布尔函数的RSA-LFSR密钥流产生器要比传统的非线性组合密钥生成器更具优越性和安全性．

英文摘要：

Key stream generator is a core part of Stream cipher. In accordance with structural thought of nonlinear combination key stream generator, a new RSA-LFSR key stream generator is proposed in this paper. The random sequences from the generator generated in combining of RSA and LFSR algorithm make combining operations with evolving Boolean function based on gene expression programming （GEP）, and output key stream. Meanwhile, safety inspections are made to the different length key se- quences generated through RSA-LFSR key stream generator. Through runs test, frequency inspection, sequential test and the calculation of linear complexity, the experiments demonstrate that RSA-LFSR key stream generator is more superiority and security than traditional nonlinear combination key generator.