Author
M. Blaze,J. Feigenbaum,P. Resnick,M. Strauss
Abstract
We address the problem of 'trust management in information labeling'. The Platform
Internet Content Selection (PICS), proposed by Resnick and Miller, establishes
a flexible way to label documents according to various aspects of their contents,
thus permitting a large and diverse group of potential viewers to make (automated)
informed judgements about whether or not to view them. For some viewers, the
relevant aspects may be quantity or quality of material in certain topical areas,
and for others, they may be the presence or absence of potentially offensive
language or images. Thus PICS users need a language in which to specify their
PICS profiles, i.e., the aspects according to which they want documents to be
labeled, the acceptable values of those labels, and the parties whom they trust
to do the labeling. Furthermore, PICS compliant client software (e.g., a web browser)
needs a mechanism for checking whether a document meets the requirements set forth
in a viewer's profile. A trust management solution for the PICS information-labeling
system must provide both a language for specifying profiles and a mechanism for
checking whether a document meets the requirements given in a profile.
This paper describes our design and implementation of a PICS profile language and
our experience integrating the PolicyMaker trust managment engine with a PICS-
compliant browser to provide a checking mechanism. PolicyMaker was originally
designed to address trust management problems in network services that process
signed requests for action and use public-key cyrptography. Because information
labeling is not inherently a cryptographically based service, and thus is outside
the original scope of the PolicyMaker framework, our work on information labeling
is evidence of PolicyMaker's power and adaptability.
