Our notion is not only useful to express the Kurosawa-Desmedt public-key encryption scheme and its generalizations to hash-proof systems in an abstract KEM/DEM security framework. It also has a very constructive appeal, which we demonstrate with a new encryption scheme whose security relies on a class of intractability assumptions that we show (in the generic group model) strictly weaker than the Decision Diffie-Hellman (DDH) assumption. This appears to be the first practical public-key encryption scheme in the literature from an algebraic assumption strictly weaker than DDH.
Category / Keywords: public-key cryptography / Chosen-ciphertext security, weak security assumptions, hybrid encryption Publication Info: A preliminary version of this paper appears in the proceedings of CRYPTO 2007. This is the full version. Date: received 27 Jul 2007 Contact author: kiltz at cwi nl Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation Version: 20070807:153308 (All versions of this report) Discussion forum: Show discussion | Start new discussion