  The emergence of cloud computing provides a new computing paradigm for users
-- massive and complex computing tasks can be outsourced to cloud servers.
However, the privacy issues also follow. Fully homomorphic encryption shows
great potential in privacy-preserving computation, yet it is not ready for
practice. At present, secure multiparty computation (MPC) remains mainly
approach to deal with sensitive data. In this paper, following the secret
sharing based MPC paradigm, we propose a secure 2-party computation scheme, in
which cloud servers can securely evaluate functions with high efficiency. We
first propose the multiplicative secret sharing (MSS) based on typical additive
secret sharing (ASS). Then, we design protocols to switch shared secret between
MSS and ASS, based on which a series of protocols for comparison and nearly all
of the elementary functions are proposed. We prove that all the proposed
protocols are Universally Composable secure in the honest-but-curious model.
Finally, we will show the remarkable progress of our protocols on both
communication efficiency and functionality completeness.
