基于Binary-LWE噪音控制优化的全同态加密方案与安全参数分析

To optimize noise management in fully homomorphic encryption scheme,a fully homomorphic encryption scheme with better parameters size was proposed.The security parameters of the scheme were estimated.Given security level,the maximal value of modulusqwas got.Then the concert security parameters of the scheme were obtained by the condition of correct decryption among noise growth,circuit depthLand modulusq.The security parameters of Bra12 scheme also was obtained by the same way.The data showed that this scheme has better parameters size.The ciphertext from homomorphic multiplication is smaller by a factor about lb²qthan in Bra12 scheme and the corresponding tensored key is smaller by a factor about lb³qthan in Bra12 scheme.The matrix of key switching is smaller by a factor about lb²qthan in Bra12 scheme.The optimization for noise management is general,which can be used in the fully homomorphic encryption schemes based on LWE in which the noise growth depends on the secret key.