网络与信息安全学报 (Jan 2017)
NTRU-type fully homomorphic encryption scheme without key switching
Abstract
In order to construct a fully homomorphic encryption scheme based on NTRU cryptosystem from ring learning with errors, noise growth and homomorphic property in the NTRU cryptosystem were analyzed. The con-cept of zero homomorphic encryption was introdced and that the NTRU cryptosystem was zero homomorphic en-cryption was shown. A BGN homomorphic encryption scheme and a fully homomorphic encryption scheme were proposed based on the NTRU cryptosystem. In the proposed NTRU-type fully homomorphic encryption scheme, the secret key doesn't change in homomorphic multiplications. Thus a fully homomorphic encryption scheme can be obtained without key switching that was used in the previous fully homomorphic encryption schemes. Moreover, the ciphertext is a vector in the proposed NTRU-type fully homomorphic encryption scheme which has the advantage of storage and transmission compared to GSW fully homomorphic encryption scheme where the ciphertext is a matrix.
