[Busec] Fwd: [Cis-seminars] Two CIS Seminars next week with Stefano Tessaro, Dec 8 & 9: Thurs and Fri

Sharon Goldberg goldbe at cs.bu.edu
Fri Dec 2 08:19:27 EST 2011


Lot's of crypto activity over the next week :)

---------- Forwarded message ----------
From: Be Blackburn <be at csail.mit.edu>
Date: Fri, Dec 2, 2011 at 8:17 AM
Subject: [Cis-seminars] Two CIS Seminars next week with Stefano
Tessaro, Dec 8 & 9: Thurs and Fri
To: cis-seminars at theory.csail.mit.edu


         MIT CIS SEMINAR
    Open To The Public

Title:       Semantic Security for the Wiretap Channel
Speaker:  Stefano Tessaro, UC San Diego
Date:       Thursday, Dec 8, 2011
Time:       9:30 am - 11:00 am
Place:       Patil/Kiva, 32-G449, Stata Center, MIT

Abstract:

The wiretap channel is a setting where one aims to get
information-theoretic privacy based only on the assumption that the
channel from sender to receiver is noisier than the one from sender to
adversary. Papers on this topic over thirty years have sought only
weak security yet failed to reach the ultimate goal of a
polynomial-time scheme of optimal rate with proven privacy over the
adversary channel and proven decodability over the receiver channel.
We not only achieve this goal but do so with strong security. We
define and prove equivalent two strong privacy metrics, one based on
semantic security and the other on entropy. We then provide a new
scheme that achieves these strong security goals in polynomial time
with optimal rate, thereby not only solving the central open problem
in this area but delivering even more in terms of security.

Joint work with Mihir Bellare and Alexander Vardy.



         MIT CIS SEMINAR
    Open To The Public

Title:   The Equivalence of the Random Oracle Model and the Ideal
    Cipher Model, Revisited.

Speaker: Stefano Tessaro, UC SanDiego
Date:    Friday, Dec 9, 2011
Time:    10:30 am - 12:00 pm
Place:     Patil/Kiva, 32-G449, Stata Center, MIT

Abstract:

We consider the cryptographic problem of constructing an
invertible random permutation from a public random function (i.e.,
which can be evaluated by the adversary). This goal is formalized by
the notion of indifferentiability of Maurer et al. (TCC 2004). This is
the natural extension to the public setting of the well-studied
problem of building random permutations from random functions, which
was first solved by Luby and Rackoff using the Feistel construction.
The most important implication of such a construction is the
equivalence of the random oracle model and the ideal cipher model.

Coron et al. (CRYPTO 2008) gave a rather involved proof that the
six-round Feistel construction with independent random round functions
is indifferentiable from an invertible random permutation. Also, it is
known that fewer than six rounds do not suffice for
indifferentiability. The first contribution (and starting point) of
our paper is a concrete distinguishing attack which shows that the
indifferentiability proof of Coron et al. is not correct. In addition,
we provide supporting evidence that an indifferentiability proof for
the six-round Feistel construction may be very hard to find.

To overcome this gap, our main contribution is a proof that the
Feistel construction with fourteen rounds is indifferentiable from an
invertible random permutation.

Joint work with Thomas Holenstein and Robin Kuenzler (STOC 2011).



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-- 
Sharon Goldberg
Computer Science, Boston University
http://www.cs.bu.edu/~goldbe



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