New notions of security: achieving universal composability without trusted setup

We propose a modification to the framework of Universally Composable (UC) security [3]. Our new notion, involves comparing the protocol executions with an ideal execution involving ideal functionalities (just as in UC-security), but allowing the environment and adversary access to some super-polynomial computational power. We argue the meaningfulness of the new notion, which in particular subsumes many of the traditional notions of security. We generalize the Universal Composition theorem of [3] to the new setting. Then under new computational assumptions, we realize secure multi-party computation (for static adversaries) without a common reference string or any other set-up assumptions, in the new framework. This is known to be impossible under the UC framework.

• Type: Conference
• Year: 2004
• Where: STOC
• Authors: Manoj Prabhakaran, Amit Sahai
• Keywords: Algorithms, Common Reference String, Secure Multi-party Computation, STOC 2004, Universal Composition Theorem