Universally Composable Synchronous Computation
In synchronous networks, protocols can achieve security guarantees that are not possible in an asynchronous world: i.e., they can simultaneously achieve input completeness (all honest parties' inputs are included in the computation) and guaranteed termination (honest parties do not "Hang" indefinitely). In practice, truly synchronous networks rarely exist, but synchrony can be emulated if channels have (known) latency and parties have loosely synchronized clocks. The framework of Universal Composability (UC) is inherently asynchronous, but several approaches for adding synchrony to the framework have been proposed. However, the authors show that the existing proposals do not provide the expected guarantees. Given this, they propose a "Clean slate" approach to defining synchrony in the UC framework by introducing functionalities exactly meant to model, respectively, bounded-delay networks and loosely synchronized clocks.