Concurrent Secure Computation via Non-Black Box Simulation
Vipul Goyal, Divya Gupta, Amit Sahai
Recently, Goyal (STOC’13) proposed a new non-black-box simulation techniques for fully concurrent zero knowledge with straight-line simulation. Unfortunately, so far this technique is limited to the setting of concurrent zero knowledge. The goal of this paper is to study what can be achieved in the setting of concurrent secure computation using non-black-box simulation techniques, building upon the work of Goyal. The main contribution of our work is a secure computation protocol in the fully concurrent setting with a straight-line simulator, that allows us to achieve several new results: • We give first positive results for concurrent blind signatures and verifiable random functions in the plain model as per the ideal/real world security definition. Our positive result is somewhat surprising in light of the impossibility result of Lindell (STOC’03) for black-box simulation. We circumvent this impossibility using non-black-box simulation. This gives us a quite natural example of a functionality in concurrent setting which is impossible to realize using black-box simulation but can be securely realized using non-black-box simulation.
•Jan 1, 2015•0 citations