一种适用于云计算环境的改进全同态加密方案

摘要

For data security requirements under the conditions of cloud computing,propose an improved fully homomorphic encryption scheme based on the existing research of fully homomorphic encryption scheme. The improved fully homomorphic encryption scheme is based on the DGHV scheme and combined with the method which changes mode 2 operation into mode 4 operation,and reduces the size of the public key,and introduce a relatively large number of fixed,forming the improved fully homomorphic encryption algorithm is more suitable for a cloud computing environment. This scheme has advantages in public key with a small size,encryption 2bit one time and without exposing the private key to the server. The improved fully homomorphic encryption scheme is compared with DGHV fully homo-morphic encryption scheme in the ciphertext retrieval. Finally,propose the applicable scenes of fully homomorphic encryption scheme un-der the conditions of cloud computing.%针对云计算环境中数据的安全性要求，在现有的全同态加密方案的研究基础上，提出了一种改进的全同态加密方案。改进的全同态加密方案在DGHV方案基础上同时结合将模2运算变为模4运算、减小公钥尺寸和引入一个比较大的固定数的方法，构成了更适合云计算环境的改进全同态加密算法。改进的全同态加密方案具有公钥尺寸小、一次加密2 bit密文和密文检索时不需要将私钥暴露给服务器的特点。文中对改进的全同态加密方案与DGHV全同态加密方案在密文检索方面进行了比较。最后提出了全同态加密方案在云计算环境中的适用场景。