  Fully homomorphic encryption is a kind of encryption scheme, which enables
arbitrary computation on encrypted data without accessing the data. We present
the quantum version of fully homomorphic encryption scheme, which is
constructed based on quantum fault-tolerant construction. Two schemes are
constructed. The first is a symmetric scheme, and the secret key is the quantum
CSS code. In the scheme, when Server performs quantum computation on the
encrypted plaintext, some ancillary quantum states should be provided by
Client. The second is an asymmetric scheme, which contains the periodical
interaction between Client and Server.
