摘要： 为防御传统自同步序列密码中普遍存在的相关攻击，以分组密码为新型序列源，提出一种基于分组密码的自同步序列密码模型。利用向量值函数的输出向量对分组密码的输出密文进行控选，以直接输出非线性密钥流，并分析模型的平衡性与完全性，证明该模型的密钥流生成器具备平衡性，且其生成密钥流与控制向量统计独立。给出线性移位寄存器状态改变1 bit密钥流概率的下界。实验结果表明，该模型可降低源信息在输出密钥流中存在的熵漏，较好地抵抗相关攻击。

关键词: 自同步, 序列密码, 分组密码, 相关攻击, 平衡性, 雪崩准则

Abstract: To resist the correlation attack against the traditional self-synchronic stream cipher, based on a new stream source——the block cipher, a self-synchronic stream cipher model is given. To output nonlinear key stream directly, the output cipher text of the block cipher is controlled and selected by the output vector of the vector-valued function, and the balance and perfectibility of the model is analyzed. The balance of the key generator, and the statistical independence of the output key stream and the control vector is proved. The lower bound probability of the key stream transforming, while LFSR transforming 1 bit, is given. Experimental result show that the entropy leakage of the source information for the output key stream can be reduced, and the correlation attack can be resisted .

Key words: self-synchronic, stream cipher, block cipher, correlation attack, balance, avalanche criterion

中图分类号: 

• TP309