可抵御唯密文攻击的基于格的公钥加密

Lattice-based public-key encryption with resistance of ciphertext-only attack

针对最新提出的对Cai-Cusick公钥加密方案的唯密文攻击进行研究,提出了一个可抵御该攻击的新的公钥加密方案。通过对原始加密方案中某些参数的修改,改变了公钥中向量长度,从而实现对原始方案攻击的有效抵御,并且通过程序模拟出新的加密方案。从数据分析可得,随着实验次数的增加,该方案抵御唯密文攻击的成功概率近似为百分之百。这说明了新的加密方案能有效抵御最新提出的唯密文攻击,且由于该方案延续了原始加密方案的加密步骤,其也具备了更少密文扩展的特性。今后将进一步研究语义安全的可抵御唯密文攻击的有效加密方案。

This paper proposed a new lattice-based public-key encryption which could resist the chosen ciphertext attack against Cai-Cusick encryption scheme. A small modification on parameters of the original scheme yielded this new scheme. This paper made a program to simulate this new scheme and found that with growth of the number of experiences, the probability of resisting chosen ciphertext was approximate to one. Hence, this new scheme could resist the attack efficiently. On the other hand, this improved encryption scheme also inherited the benefits from the original scheme, of less ciphertext expansion. It draw a conclusion that this scheme has less ciphertext expansion and can prevent the ciphertext-only attack.