AnonimityCommunication - On Anonymity in an Electronic...

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On Anonymity in an Electronic Society:
A Survey of Anonymous Communication Systems
MATTHEW EDMAN and B
¨
ULENT YENER
Rensselaer Polytechnic Institute
The past two decades have seen a growing interest in methods for anonymous communication on the Internet,
both from the academic community and the general public. Several system designs have been proposed in the
literature, of which a number have been implemented and are used by diverse groups, such as journalists,
human rights workers, the military, and ordinary citizens, to protect their identities on the Internet.
In this work, we survey the previous research done to design, develop, and deploy systems for enabling
private and anonymous communication on the Internet. We identify and describe the major concepts and
technologies in the field, including mixes and mix networks, onion routing, and Dining Cryptographers
networks. We will also review powerful traffic analysis attacks that have motivated improvements and
variations on many of these anonymity protocols made since their introduction. Finally, we will summarize
some of the major open problems in anonymous communication research and discuss possible directions for
future work in the field.
Categories and Subject Descriptors: C.2.0 [ Computer-Communication Networks ]: General— Security
and protection (e.g. firewalls) ; C.2.2 [ Computer-Communication Networks ]: Network Protocols— Applica-
tions (SMTP, FTP, etc.) ; C.2.4 [ Computer-Communication Networks ]: Distributed Systems— Distributed
applications ; K.4.1 [ Computers and Society ]: Public Policy Issues— Privacy
General Terms: Security
Additional Key Words and Phrases: Anonymity, anonymous communication, DC-nets, mixes, mix networks,
onion routing, privacy, traffic analysis
ACM Reference Format:
Edman, M. and Yener, B. 2009. On anonymity in an electronic society: A survey of anonymous communication
systems. ACM Comput. Surv. 42, 1, Article 5 (December 2009), 35 pages.
DOI = 10.1145/1592451.1592456, http://doi.acm.org/10.1145/1592451.1592456
1. INTRODUCTION
A famous cartoon in The New Yorker once carried the caption, “On the Internet, nobody
knows you’re a dog” [Steiner 1993]. This phrase symbolizes the general public’s percep-
tion that the Internet allows one to communicate in relative obscurity and anonymity.
Quite the contrary, today’s modern communications infrastructure is indeed capable of
identifying and recording what we do, where we go, and even sometimes what we say
on the Internet.
Author’s address: Department of Computer Science, Rensselaer Polytechnic Institute, 110 8
th
Street, Troy,
NY 12180; email: { edmanm2,yener } @cs.rpi.edu.
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