标准模型下具有IND-CCA2安全的混合加密方案

摘要

This paper improved the classical generating trapdoor algorithm based on a variant of ideal-SIS(ideal small integer solution)by Damien Stehle.What’s more,the new scheme improved a chosen-plaintext attacks security scheme by Damien Stehle .Then,combining with SWIFFT compression functions,it designed an indistinguishable against adaptive chosen-cipher-text attacks secure hybrid encryption scheme in the standard model.In this process,the new scheme required n log q less de-scription bit.It could process string from n log q bit to m ×n log q bit in the encryption and decryption processing.There is a huge improvement in key size and speed for these schemes.%基于ideal-SIS（ideal small integer solution）的一个变种，改进了Damien Stehle的陷门生成算法。利用改进的陷门生成算法对Stehle的选择明文攻击（CPA）安全方案进行了改进，然后结合SWIFFT压缩函数，提出了一种在标准模型下达到适应性选择密文攻击下的不可区分性（IND-CCA2）安全的混合加密方案。在该陷门产生过程中节省了n log q bit的描述位；与原有方案相比，新方案一次加解密的字符长度从n log q bit提高到了m ×n log q。基于上述改进，新方案在运行所需的时间和空间效率方面有了很大的提高。