To meet such a practical requirement, we first introduce proxy re-encryption with non-interactive opening (PRENO), and formally define the notions of security against \textit{chosen ciphertext attacks} (CCA) and \textit{proof soundness}. Our security model is natural and strong since we allow the CCA adversary to adaptively choose public keys for malicious users (i.e., a chosen key model), and a scheme secure in previous models (i.e., knowledge of secret key models) is not necessarily secure in our model. Then, we present an efficient PRENO scheme which satisfies our security notions based on the decisional bilinear Diffie-Hellman (DBDH) assumption in the standard model. Compared with two previous PRE schemes, our scheme is competitive in several aspects. First, its CCA security is proved in a strong security model under a well-studied assumption in the standard model. Second, it has a good overall performance in terms of ciphertext length and computational cost. Third, it first provides non-interactive opening for PRE schemes.
Category / Keywords: public-key cryptography / Proxy Re-Encryption, Chosen Key Model, CCA Security, Non-interactive Opening Date: received 23 Nov 2012, last revised 3 Dec 2012 Contact author: jiangzhang09 at gmail com Available format(s): PDF | BibTeX Citation Version: 20121203:145623 (All versions of this report) Short URL: ia.cr/2012/664