Concurrently Composable Security With Shielded Super-polynomial Simulators.
Brandon Broadnax, Nico Döttling, Gunnar Hartung, Jörn Müller‐Quade, Matthias Nagel · IACR Cryptology ePrint Archive · 2016
We propose a new framework for concurrently composable security that relaxes the security notion of UC security. As in previous frameworks, our notion is based on the idea of providing the simulator with super-polynomial resources. However, in our new framework simulators are only given restricted access to the results computed in super-polynomial time. This is done by modeling the super-polynomial resource as a stateful oracle that may directly interact with a functionality without the simulator seeing the communication. We call these oracles “shielded oracles”.