Universally Composable Symmetric Encryption

Abstract—For most basic cryptographic tasks, such as public-key encryption, digital signatures, authentication, key exchange, and many other more sophisticated tasks, ideal functionalities have been formulated in the simulation-based security approach, along with their realizations. Surprisingly, however, no such functionality exists for symmetric encryption, except for a more abstract Dolev-Yao style functionality. In this paper, we fill this gap. We propose two functionalities for sym-metric encryption, an unauthenticated and an authenticated version, and show that they can be implemented based on standard cryptographic assumptions for symmetric encryption schemes, namely IND-CCA security and authenticated encryp-tion, respectively, provided that the environment does not create key cycles or cause the so-called commitment problem. We also illustrate the usefulness of our functionalities in applications, both in simulation-based and game-based security settings. I