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dc.contributor.advisorShafi Goldwasser
dc.contributor.authorPass, Rafael
dc.contributor.authorShelat, Abhi
dc.contributor.authorVaikuntanathan, Vinod
dc.contributor.otherTheory of Computation
dc.date.accessioned2006-12-14T14:51:47Z
dc.date.available2006-12-14T14:51:47Z
dc.date.issued2006-12-14
dc.identifier.otherMIT-CSAIL-TR-2006-081
dc.identifier.urihttp://hdl.handle.net/1721.1/34968
dc.description.abstractUnder an adaptive chosen ciphertext attack (CCA2), the security of an encryption scheme must hold against adversaries that have access to a decryption oracle. We consider a weakening of CCA2 security, wherein security need only hold against adversaries making an a-priori bounded number of queries to the decryption oracle. Concerning this notion, which we call bounded-CCA2 security, we show the following two results. (1) Bounded-CCA2 secure non-malleable encryption schemes exist if and only if semantically-secure (IND-CPA-secure) encryption schemes exist.(As far as we know, bounded-CCA2 non-malleability is the strongest notion of security known to be satisfiable assuming only the existence of semantically-secure encryption schemes.) (2) In contrast to CCA2 security, bounded-CCA2 security alone does not imply non-malleability. In particular, if there exists an encryption scheme that is bounded-CCA2 secure, then there exists another encryption scheme which remains bounded-CCA2 secure, but is malleable under a simple chosen-plaintext attack.
dc.format.extent17 p.
dc.format.extent1222225 bytes
dc.format.extent239045 bytes
dc.format.mimetypeapplication/postscript
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.relation.ispartofseriesMassachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory
dc.subjectPublic-key Encryption
dc.subjectNon-Malleability
dc.subjectChosen Ciphertext Security
dc.titleBounded CCA2-Secure Non-Malleable Encryption


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