\emph{Adaptive security} for public-key encryption schemes is an important security notion that was proposed by Canetti et al.\ over 15 years ago. It is intended to ensure security when encryption is used within an interactive protocol, and parties may be \emph{adaptively} corrupted by an adversary during the course of the protocol execution. Due to the extensive applications of FHE to protocol design, it is natural to understand whether adaptively secure FHE is achievable.
In this paper we show two contrasting results in this direction. First, we show that adaptive security is \emph{impossible} for FHE satisfying the (standard) \emph{compactness} requirement. On the other hand, we show a construction of adaptively secure FHE that is not compact, but which does achieve circuit privacy.
Category / Keywords: Original Publication (in the same form): IACR-PKC-2013 Date: received 24 Mar 2015 Contact author: aish at cs umd edu Available format(s): PDF | BibTeX Citation Version: 20150325:124527 (All versions of this report) Short URL: ia.cr/2015/280 Discussion forum: Show discussion | Start new discussion