Many information services in pervasive computing offer {\it rich}
information, which is information that includes other types of
information.  For example, the information listed in a person's
calendar entry can reveal information about the person's location or
activity.  To avoid rich information from leaking its included
information, we must consider the semantics of the rich information
when controlling access to this information.  Other approaches that
reason about the semantics of information (e.g., based on Semantic Web
rule engines) are based on a centralized design, whose drawback is a
single point of failure.  In this paper, we exploit {\it information
relationships} for capturing the semantics of information.  We
identify three types of information relationships that are common and
important in pervasive computing and integrate support for them in a
distributed, certificate-based access control architecture.  In the
architecture, individuals can either define their own information
relationships or refer to relationships defined by a standardization
organization.  In our approach, access control is fully distributed
while sophisticated rule engines can still be used to deal with more
complex access control cases.  To demonstrate the feasibility of our
design, we give a complexity analysis of the architecture and a
performance analysis of a prototype implementation.