Abstract: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 modulus q was got.Then the concert security parameters of the scheme were obtained by the condition of correct decryption among noise growth

circuit depth L and modulus q.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 lb2 q than in Bra12 scheme and the corresponding tensored key is smaller by a factor about lb3 q than in Bra12 scheme.The matrix of key switching is smaller by a factor about lb2 q than 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.