An increasing number of web-sites require users to establish an account
before they can access the information stored on that site
(``personalized web browsing''). Typically, the user is required to
provide at least a unique username, a secret password and an e-mail
address. Establishing accounts at multiple web-sites is a tedious
task. A security- and privacy-aware user may have to invent a
distinct username and a secure password, both unrelated to his/her
identity, for each web-site. The user may also desire mechanisms for
anonymous e-mail. Besides the information that the user supplies
voluntarily to the web-site, additional information about the user may
flow (involuntarily) from the user's site to the web-site, due to the
nature of the HTTP protocol and the Cookie mechanism.
In this talk we will describe the Personalized Web Anonymizer (PWA),
which makes personalized web browsing simple, secure and anonymous by
providing convenient solutions to each of the above problems. The PWA
serves as an intermediary entity between a user and a web-site. Given
a user and a web-site, the PWA automatically generates an alias --
typically a username, a password and an e-mail address -- that can be
used to establish an anonymous account at the web-site. Different
aliases are generated for each user, web-site pair; however the same
alias is presented whenever a particular user visits a particular
web-site. The PWA frees the user from the burden of inventing and
memorizing distinct usernames and secure passwords for each web-site,
and guarantees that an alias (including an e-mail address) does not
reveal the true identity of the user. The PWA also provides mechanisms
to complete an anonymous e-mail exchange from a web-site to a user,
and filters the information-flow of the HTTP protocol to preserve
user privacy. Thus PWA provides simultaneous user identification
and user privacy, as required for anonymous personalized web browsing.
Joint work with Eran Gabber, Phil Gibbons, David M. Kristol and Alain Mayer