SPEAKER: Aristeidis Tentes TITLE: Key Dependent Message Secure Schemes AUTHORS: ABSTRACT: Roughly speaking, KDM secure schemes are CPA secure encryption schemes, where the adversary is even allowed to ask for encryptions of h(sk), where h belongs to some function family H and sk the secret key. We are going to cover the scheme of BHHO08, where H is the family of affine functions and its security is based on DDH assumption. Then we will see how we can use this scheme to construct a bounded KDM secure scheme, where H is the set of all functions which can be computed by circuits of bounded size. In the proof of security of the latter scheme the query function is used in a non black box way and we will see that this fact is actually inherent. These results are included in BHHI09. LINKS (Related Papers): [BHHO09]: Dan Boneh, Shai Halevi, Michael Hamburg, Rafail Ostrovsky: Circular-Secure Encryption from Decision Diffie-Hellman. CRYPTO 2008: 108-125 http://www.cs.ucla.edu/~rafail/PUBLIC/97.pdf [BHHI09]: Boaz Barak, Iftach Haitner, Dennis Hofheinz, Yuval Ishai: Bounded Key-Dependent Message Security http://eprint.iacr.org/2009/511.pdf