We give the first perfectly rerandomizable, Replayable-CCA (RCCA) secure encryption scheme, positively answering an open problem of Canetti et al. (CRYPTO 2003). Our encryption scheme, which we call the Double-strand Cramer-Shoup scheme, is a non-trivial extension of the popular Cramer-Shoup encryption. Its security is based on the standard DDH assumption. To justify our definitions, we define a powerful "Replayable Message Posting" functionality in the Universally Composable (UC) framework, and show that any encryption scheme that satisfies our definitions of rerandomizability and RCCA security is a UC-secure implementation of this functionality. Finally, we enhance the notion of rerandomizable RCCA security by adding a receiver-anonymity (or keyprivacy) requirement, and show that it results in a correspondingly enhanced UC functionality. We leave open the problem of constructing a scheme achieving this enhancement. © International Association for Cryptologic Research 2007.
CITATION STYLE
Prabhakaran, M., & Rosulek, M. (2007). Rerandomizable RCCA encryption. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 4622 LNCS, pp. 517–534). Springer Verlag. https://doi.org/10.1007/978-3-540-74143-5_29
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