Lightweight Privacy-Preserving (t, m, n) Multi-Party Computation Based on Secret Sharing in Untrusted Cloud Environments

Abstract

The next generation of Internet of Things (IoT) networks and mobile communications (5G IoT networks) has the particularity of being heterogeneous, therefore, it has very strong ability to compute, store, etc. Group-oriented applications demonstrate its potential ability in Untrusted Cloud Environments (UCE). One of the main challenges for secure group-oriented applications (SGA) in UCE is how to secure communication and computation between these heterogeneous devices. Conventional protocols are not suitable for SGA in UCE since multiparty secure computation in this environment requires lightweight communication and computation overhead. Multi-Party Computation (MPC) takes multiple inputs and outputs their sum/product without revealing each individual input. MPC has found ways in electronic voting, electronic auctions, electronic cash schemes, contract signing, etc. Motivated by the first arithmetic MPC protocol (also known as BGW protocol) proposed by Ben-Or et al. based on the secret sharing scheme, in this paper, we give a novel definition, called (t, m, n) MPC, where m is the number of data inputs, t is a threshold and n is the number of shares, which is similar to the definition of a (t, n) secret sharing scheme; but with some additional security requirements. BGW is a (t, m, n) MPC but has following limitations, (1) BGW cannot be used to implement a (m, m, m) MPC; and (2) in computing multiplicative product, BGW needs degree-reduction process which is a communication intensive process. In this paper, we propose a simple and lightweight (m, m, m) MPC which involves only additions/multiplications. Then, we extend our simple (m, m, m) MPC to design a general (t, m, n) MPC. Our proposed MPC is more efficient than BGW since our MPC does not need degree-reduction process. It is really attractive for lightweight privacy-preserving multi-party computation in UCE.