[talks] Michael J Freedman, Mon Nov 20, 1:30

Vivek Pai vivek at CS.Princeton.EDU
Thu Nov 16 12:57:38 EST 2006

Michael J Freedman, the NYU graduate student, will be
speaking on Monday at 1:30 in room 402. His talk title and
abstract are included below. If you'd like to talk with
him, please sign up in

Just to avoid some confusion that occurred the last time
he visited, please note that this is not Michael H. Freedman,
the Fields Medal winner.


RE: Fighting Spam with Reliability and Privacy

  Mike Freedman

  NYU / Stanford
  mfreed at scs.stanford.edu


The explosive growth in unwanted email has prompted the development of
techniques for the rejection of email, intended to shield recipients
from the onerous task of identifying the legitimate email in their
inboxes amid a sea of spam. Unfortunately, widely-used content-based
filtering systems have converted the spam problem into a false
positive one: Email has become unreliable.

We present Reliable Email (RE: [1]), a new whitelisting system that
incurs zero false positives among socially-connected users yet
populates whitelists automatically by exploiting transitive trust
relationships.  Further, while RE: permits a recipient to discover
whether other users have whitelisted the sender, it preserves the
privacy of email contacts with a cryptographic Private Matching [2]
protocol. Using real email traces from two sites, we demonstrate that
RE: renders a significant fraction of received email reliable. Our
evaluation also shows that RE: can prevent up to 88% of the false
positives incurred by common email rejection systems.

Finally, we propose a more formal definition of security for verifying
social connectedness in a privacy-preserving fashion [3]. In the
process, we identify a mismatch between RE:'s goals and [2]'s
properties, enabling us to construct new cryptographic protocols that
are either more efficient (based only on symmetric operations) or
achieve stronger guarantees (namely, non-transferability) through
bilinear pairings.  Using such, RE: can provide privacy-preserving
social whitelisting with millisecond overhead.

 1. Re: Reliable Email
    Garriss, Kaminsky, Freedman, Karp, Mazieres, and Yu, NSDI '06

 2. Efficient Private Matching and Set Intersection
    Freedman, Nissim, and Pinkas, EUROCRYPT '04

 3. Efficient Private Techniques for Verifying Social Proximity
    Freedman and Nicolosi, Submitted Nov '06


Michael J. Freedman is a doctoral student at NYU, currently visiting
Stanford University.  He received his M.Eng. and S.B. degrees from
MIT.  His research interests broadly focus on security, distributed
systems, and cryptography.  Among other things, he developed the Coral
content distribution network and OASIS anycast service, which serve
more than a million users daily (see www.coralcdn.org).  In 2006, he
co-founded Illuminics Systems, which has been acquired by Quova, Inc.

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