对用于密码学的山农信息理论的研究作了评论并加以推广。证明山农的随机密码模型是保守的,在此模型中,随机选择密码本质上是一种最坏可能的密码。将它和纠错编码相比较,随机选择编码本质上则是一种最好可能的编码。还提出了密码与语言相匹配的概念以及调整局部和总体间的不可靠性的概念。 The research on Shannon information theory used in cryptography was commented and promoted. Prove Shannon’s random password model is conservative, in this model, random selection of the password is essentially the worst possible password. Comparing it with error correction coding, random selection coding is essentially the best possible coding. Also put forward the concept of password and language match and adjust the concept of local and overall unreliability.