一种NTRU格上基于身份全同态加密体制设计

全同态加密可以用来解决云计算环境中的隐私保护问题，然而现有体制具有系统参数大、效率低的缺点.针对现有攻击技术，首先设计了一种高效的NTRU格上的基于身份公钥加密体制，无需借助额外的安全性假设，具有更高的安全性和更小的系统参数.之后，基于近似特征向量技术，构造了一种高效的全同态加密转化方式.通过将以上两种方法结合，给出了一种高效的基于身份全同态加密体制.和现有体制相比，除了不需要计算密钥、实现了真正意义上的基于身份特性以外，还减小了密钥、密文尺寸，提高了计算和传输效率.

An Identity-Based Fully Homomorphic Encryption Over NTRU Lattice

Fully homomorphic encryption can be used to solve privacy concerns for data over cloud,while large parameters and low efficiency are the universal issues for present schemes.To oppose mainstream attacks,an identity-based public key scheme over NTRU lattice with smaller parameters,higher security level,and without additional security assumptions is put forward.Take advantage of the approximate eigenvector technique,an efficient fully homomorphic encryption transformation method is raised.And by combining the two skills above,an efficient identity-based fully homomorphic encryption scheme is proposed.Compared with existing schemes,the schemes is fully identity-based without evaluation key,and has smaller keys and ciphertext sizes,leading to higher transmission and computational efficiency.