  Blind quantum computation (BQC) provides an efficient method for the client
who does not have enough sophisticated technology and knowledge to perform
universal quantum computation. The single-server BQC protocol requires the
client to have some minimum quantum ability, while the double-server BQC
protocol makes the client's device completely classical, resorting to the pure
and clean Bell-state shared by two servers. In this paper, we provide a
deterministic entanglement distillation protocol in a practical noisy
environment for the double-server BQC protocol. This protocol can obtain the
pure maximally entangled Bell state with the success probability of 100% in
principle. The distilled maximally entangled states can be remaind to perform
the BQC protocol subsequently. The parties who perform the distillation
protocol do not need to exchange the classical information and they learn
nothing from the client. It makes this protocol unconditionally secure and
suitable for current BQC protocol.
