10:0010:30  Coffee/Tea 
10:3011:15  Mridul Nandi 
A view on Indistinguishability, A popular security
notion in Symmetric Cryptography 
 In this seminar, I would like to present how one can make an indistinguishability security analysis in a concrete and simple way. Intuitively, indistinguishability means that it is difficult to distinguish between two classes of
ob jects, say two families of functions. Most of the literatures regarding indistinguishability have been made by using game playing approach. In this
talk, I would present a mathematically concrete analysis which can be made
in a simpler way than the game playing techniques. I would also like to
point out that many well known proofs contain serious mistakes. I have
proved many well known results (including the result containing mistakes)
by the concrete framework for indistinguishability. I have also found several
modified results. For example,
 more efficient online ciphers than existing ones,
 a wider class of DAG based PRF which contains many constructions
like PMAC, XCBC, TMAC, OMAC,
 an improved security bound for PMAC and
 indifferentiability for several designs of hash functions including double
block length hash functions and EMD hash functions.
Thus I have unified many indistinguishability results and put into a
common framework (as much as possible) and have provided a concrete and
simple security analysis. I expect this direction of research would help us to
have many more interesting results in future.

11:1512:00  John P. Steinberger 
Tilings and Vanishings 
 The speaker will present some of his results on translational tilings of the integers by finite sets and their connection to vanishing sums of roots of unity. 
12:0013:30  Lunch (not included) 
13:3014:15  Peter Malkin 
Groebner bases and Markov bases of Integer Programs 
 I will present new algorithms for computing Groebner bases and Markov bases of integer programs, which are in general much faster than previous methods. 
14:1515:00  Enav Weinreb 
Secret Sharing Schemes  Complexity Issues and Constructions 
 Secret sharing schemes enable a dealer to share a secret among a set of players such that only some predetermined subsets of the players can reconstruct the secret from their shares. Most of the known secret sharing schemes are designed using linear algebraic techniques. We prove that nonlinear secret sharing schemes are stronger than their linear counterparts, and show some efficient constructions of secret sharing schemes. 
15:0015:15  Coffee/Tea 
15:1516:00  Benjamin Kane 
Computationally Feasible Bounds for Quadratic Forms and CM Lifts of Supersingular Elliptic Curves 
 For a supersingular elliptic curve E, we use a correspondence between lifts to elliptic curves with CM by O_{D} and representations of D by a certain quadratic form to show an explicit bound D_E, conditional upon GRH, for which a lift exists whenver D>D_E. 
16:00  Informal drinks in DIAMANT room 