流密码的比特安全性

On Bit Security of Stream Ciphers

流密码的比特安全性是衡量密码体制好坏的重要指标。本文把流密码看作一个有记忆系统对其比特安全性进行了讨论。本文研究的模型包括线性移位寄存器序列，前馈序列和钟控序列。通过研究它们的比特安全性，可以对这些流密码体制在局部范围的安全程度有新的认识。

Bit security is one of the important indexes on measuring stream ciphers.This paper discusses the security of stream ciphers by treating them as systems with memory.The models studied in this paper include linear shift register sequences,feedforward sequences and clock controlled sequences.The results may be helpful for some new realization of the local security of stream cipher systems.