Type of Talk:  UTCS Cryptography and Network Security

Seminar

Speaker/Affiliation: Amit Sahai/UCLA

Date/Time: 
Friday, May 8, 2009 11:00 a.m.

Location:  ACES 2.402

H

ost: Brent Waters

Talk Title:  "A New Paradigm for Secure
Protocols"

Talk Abstract:

One of the most fundamental go

als in cryptography is to design protocols that remain secure when adversar

ial participants can engage in arbitrary malicious behavior.  In 1986

, Goldreich, Micali, and Wigderson presented a powerful paradigm for des

igning such protocols: their approach reduced the task of designing secure

protocols to designing protocols that only guarantee security against &quot

;honest-but-curious" participants. By making use of zero-knowledge p

roofs, the GMW paradigm enforces honest behavior without compromising secr

ecy.  Over the past two decades, this approach has been the dominant
paradigm for cryptographic protocol design.

In this talk, we p

resent a new general paradigm for secure protocol design. Our approach also
reduces the task of designing secure protocols to designing protocols that
only guarantee security against honest-but-curious participants.  Ho

wever, our approach avoids the use of zero-knowledge proofs, and instead

makes use of multi-party protocols in a much simpler setting - where the ma

jority of participants are completely honest (such multi-party protocols ca

n exist without requiring any computational assumptions).  Our paradi

gm yields protocols that rely on Oblivious Transfer (OT) as a building bloc

k.  This offers a number of advantages in generality and
efficie

ncy.

In contrast to the GMW paradigm, by avoiding the use of ze

ro-knowledge proofs, our paradigm is able to treat all of its building blo

cks as "black boxes". This allows us to improve over previous r

esults in the area of secure computation. In particular, we obtain:
<

br />* Conceptually simpler and more efficient ways for basing unconditiona

lly secure cryptography on OT.

* More efficient protocols for ge

nerating a large number of OTs using a small number of OTs.

* Se

cure and efficient protocols which only make a black-box use of cryptograph

ic primitives or underlying algebraic structures in settings where no such

protocols were known before.

This talk is based on joint works w

ith Yuvali Ishai (Technion and UCLA) and Manoj Prabhakaran (UIUC).

S

peaker Bio:

Professor Amit Sahai received his Ph.D. in Computer Scien

ce from MIT in 2000. From 2000 to 2004, he was a professor at Princeton Un

iversity; in 2004 he joined UCLA as an Associate Professor of Computer Sci

ence, and as Associate Director of the Center for Information and Computat

ion Security. His research interests are in security and cryptography, and
theoretical computer science more broadly. He has published more than 60 o

riginal technical research papers at venues such as the ACM Symposium on Th

eory of Computing (STOC), CRYPTO, and the Journal of the ACM. He has give

n a number of invited talks at institutions such as MIT, Stanford, and Be

rkeley, including the 2004 Distinguished Cryptographer Lecture Series at N

TT Labs, Japan. Professor Sahai is the recipient of numerous honors; he w

as named an Alfred P. Sloan Foundation Research Fellow in 2002, and receiv

ed an Okawa Research Award in 2007. His research has been covered by severa

l news agencies including the BBC World Service.

*Special Note: This

talk will be part of the Cryptography and Network Security Seminar. The sem

inar was recently created to bring together ideas in cryptography and syste

ms security. We are happy to have Amit Sahai as our inaugural and distingui

shed speaker of our seminar.