单向函数与对称密码体制  

One-way Function and Symmetrical Cryptosystem

作　　者：童亚拉[1] 

机构地区：[1]湖北工业大学理学院,湖北武汉430068

出　　处：《河南理工大学学报（自然科学版）》2006年第4期338-340,共3页Journal of Henan Polytechnic University（Natural Science）

基　　金：高等学校博士学科专项科研基金资助项目(20030486049)

摘　　要：可靠的密码学是建立在数学和形式化的计算机科学产生的结论之上的,本文从计算理论的角度阐述了构建对称密码体制所需的数学背景:算法复杂性与问题复杂性的关系;NP问题与密码学的关系;密钥长度与密码安全的关系.从保长和置换的概念入手,说明了构造对称密码体制的理论基础———单向置换和单向函数,并以计算机口令系统为实例说明了如何构造对称密码系统.Reliable cryptograph is set up in math and formal computer science. According to the computational theory, the paper expounds mathematical background for public-key cryptosystem including： the complexity of algorithm and problem, relationship between the length of key and security of cryptogram. And also in the concept of length holding and permutation, one-side permutation and one-way Function, which are the theoretical base of constructing symmetrical cryptosystem are introduced. Finally as an applying example, password system in computer shows how to construct symmetrical cryptosystem.

关 键 词：复杂性 可计算性理论 密钥 单向置换 单向函数 对称密码体制 

分 类 号：TP301.5[自动化与计算机技术—计算机系统结构]