[Busec] The Second Charles River Crypto day: Friday Nov 30 at BU's Hariri inst.

Ran Canetti canetti at bu.edu
Wed Nov 21 17:25:59 EST 2012


Dear All:

You are cordially invited to the second Charles River Crypto Day, to be
held at  the Hariri Institute in Boston University on Friday, November 
30, 2011.
The program appears below. The event is open to the public. Please 
circulate!

Shafi, Yael, Ran


Venue and parking: The location is the same as last year. The address is 
111 Cummington mall, Room 180. The closest entrance is at the corner of 
Cummington Mall and Hinsdale st. If you need parking permit at the 
adjacent parking structure (entrance from Hinsdale st), please send an 
email with your license plate number to Ran.


Program:
========

10:00 - 11:00
Functional Encryption, Reusable Garbled Circuits and more
Vinod Vaikuntanathan, University of Toronto

11:30 - 12:30
Delegation for Bounded Space
Ran Raz, Weizmann Institute and IAS

Lunch (provided)

1:30  - 2:30
Reduction-Resilient Cryptography:  Security Goals that Resist
Reductions from All Standard Assumptions
Daniel Wichs, IBM Research

2:45  - 3:45
The Computational Complexity of Differential Privacy
Salil Vadhan, Harvard University


============================================================================

Abstracts:

============================================================================

Functional Encryption, Reusable Garbled Circuits and more

Vinod Vaikuntanathan, University of Toronto

We construct a functional encryption scheme for all circuits, where the
size of the ciphertext grows with the depth of the circuit. Previously, 
the only known constructions of functional encryption were either for 
specific inner product predicates, or for a weak form of functional 
encryption where the ciphertext size grows with the *size* of the 
circuit for f. Our constructions are secure under the learning with 
errors assumption.


We demonstrate the power of this result, by using it to construct a 
reusable circuit garbling scheme with input and circuit privacy: an open 
problem that was studied extensively by the cryptographic community 
during the past 30 years since Yao’s introduction of a one-time circuit 
garbling method in the mid 80’s. Our scheme also leads to a new paradigm 
for general function obfuscation which we call token-based obfuscation.


=========================================================================

Reduction-Resilient Cryptography:  Security Goals that Resist
Reductions from All Standard Assumptions

Daniel Wichs, IBM Research

Abstract: This talk will explore several recent black-box separation
results with a common theme: some desirable security notions have a
"non-standard" structure that resists black-box reductions from all
"standard" assumptions. We formalize the notion of  "standard"
assumptions and security notions as ones that have the format of a
(possibly interactive) game between a challenger and an attacker,
where the challenger interacts with the attacker as a black box. This
captures essentially all of our favorite cryptographic assumptions
including: FACTORING, CDH, DDH, RSA. LWE, etc. The "non-standard"
security notions we explore appear diverse,  but have a common thread
of reasoning about adversarial distributions and leakage. In
particular, we give separation results for: leakage-resilience with a
unique secret, deterministic encryption on correlated messages, tools
for generating and condensing pseudo-entropy, and instantiating the
Fiat-Shamir heuristic for all proof-systems.

This talk is partially based on joint work with Nir Bitansky and Sanjam 
Garg.



=============================================================================


The Computational Complexity of Differential Privacy

Salil Vadhan
Harvard University

Abstract:
A major challenge in data privacy research is to enable the wide 
analysis of datasets with potentially sensitive information about 
individuals, while ensuring that the privacy of those individuals is 
protected.  Over the past decade, differential privacy has emerged as 
strong privacy protection model that supports a very rich variety of 
useful analyses.  However, computational complexity has turned out to be 
an obstacle for achieving one of the most exciting possibilities of 
differential privacy --- noninteractively publishing a private "summary" 
of a dataset that enables answering up to exponentially many statistical 
queries about the dataset (such as all multivariate marginal statistics).

Whether these complexity barriers can be broken remains an intriguing 
open problem, but we will describe both negative and positive results 
that shed light on what can be achieved.  On the negative side, we prove 
that if we require the summary to be a "synthetic dataset," then 
generating the summary is as hard as forging digital signatures, even if 
we want to preserve very simple statistics (2-way marginals, i.e. 
correlations between pairs of attributes).  On the positive side, we 
provide an algorithm for generating less structured summaries (based on 
polynomial approximations) in subexponential time, even for an 
exponential-sized family of statistics (all multivariate marginals).

Based on joint works with Justin Thaler and Jon Ullman.

============================================================================

We wish to thank BU's Rafik B. Hariri Institute for Computing and
Computational Science & Engineering  and the Center for Reliable 
Information
Systems and Cyber Security (RISCS) for making this event possible via
generous support.




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