G.: Universally composable key-management

Abstract. We present the first universally composable key-management func-tionality, formalized in the GNUC framework by Hofheinz and Shoup. It allows the enforcement of a wide range of security policies and can be extended by di-verse key usage operations with no need to repeat the security proof. We illustrate its use by proving an implementation of a security token secure with respect to arbitrary key-usage operations and explore a proof technique that allows the stor-age of cryptographic keys externally, a novel development in simulation-based security frameworks.