构造安全有效的概率公开钥密码体制的一般方法

A GENERAL ALGORITHMIC SCHEME FOR CONSTRUCTING SECURE AND EFFICIENT PROBABILISTIC PUBLIC KEY CRYPTOSYSTEM

本文首先提出了“B-f-△条件”,这一条件的存在性等价于单向陷门函数的存在性.基于这一条件,文中给出了构造具有多项式安全性的概率公开钥密码体制的一般方法,其密文长至多为明文长加上体制的规模参数.从而解决了概率公开钥密码体制中密文扩张率太大的问题.

In this paper, 'B-f-Δ' condition is presented, the existence of which is equivalent to that of one-way trapdoor function. Based on this condition, a general algorithmic scheme for constructing polynomially secure probabilistic public key cryptosystem (PPKC) is given. The problem of great message expansion in PPKC is solved in that the length of cyphe-rtext is at most l + k, where l is the length of cleartext and k the size parameter of system.