Universally Composable Signcryption

摘要

One of the challenges within public-key based cryptosystems is providing the user with a convenient interface, while retaining security. In the universal composability framework, we propose an ideal functionality for secure messaging, with a user-friendly interface. We also propose an ideal functionality for signcryption, and we show that, given a public key infrastructure and a secure signcryption protocol, we can construct a protocol that securely realizes the secure messaging functionality. Moreover, we show that a signcryption protocol realizes the signcryption functionality if and only if the corresponding signcryption scheme is secure.