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.