SPEAKER: Joël Alwen TITLE: Efficient lattice (H)IBE in the standard model continued AUTHORS: S. Agrawal, D. Boneh, and X. Boyen X. Boyen ABSTRACT: We construct an efficient identity based encryption system based on the standard learning with errors (LWE) problem. Our security proof holds in the standard model. The key step in the construction is a family of lattices for which there are two distinct trapdoors for finding short vectors. One trapdoor enables the real system to generate short vectors in all lattices in the family. The other trapdoor enables the simulator to generate short vectors for all lattices in the family except for one. We extend this basic technique to an adaptively-secure IBE and a Hierarchical IBE. Time permiting, we will also cover the results in "Lattice Mixing and Vanishing Trapdoors" by Xavier Boyen which appeared in PKC 2010. ABSTRACT: We propose a framework for adaptive security from hard random lattices in the standard model. Our approach borrows from the recent Agrawal-Boneh-Boyen families of lattices, which can admit reliable and punctured trapdoors, respectively used in reality and in simulation. We extend this idea to make the simulation trapdoors cancel not for a specific target but on a non-negligible subset of the possible challenges. Conceptually, we build a compactly representable, large family of input-dependent ``mixture'' lattices, set up with trapdoors that ``vanish'' for a secret subset wherein we hope the attack occurs. Technically, we tweak the lattice structure to achieve ``naturally nice'' distributions for arbitrary choices of subset size. The framework is very general. Here we obtain fully secure signatures, and also IBE, that are compact, simple, and elegant. LINKS: http://users.ece.utexas.edu/~sagrawal/papers/abb_efficient_ibe.pdf http://ai.stanford.edu/~xb/pkc10b/index.html