Concurrently Secure Computation in Constant Rounds

The authors study the problem of constructing concurrently secure computation protocols in the plain model, where no trust is required in any party or setup. While the well established UC framework for concurrent security is impossible to achieve in this setting, a meaningful notion of concurrent security based on Super-Polynomial Simulation (SPS) is achievable and has been extensively studied [Pas03, PS04, BS05, LPV09, CLP10]. The recent work of [CLP10] obtains a concurrently secure computation protocol in the plain model with SPS security under standard assumptions, but requires a number of rounds of interaction that is polynomial in the security parameter.