  Content-Centric Networking (CCN) is an emerging network architecture designed
to overcome limitations of the current IP-based Internet. One of the
fundamental tenets of CCN is that data, or content, is a named and addressable
entity in the network. Consumers request content by issuing interest messages
with the desired content name. These interests are forwarded by routers to
producers, and the resulting content object is returned and optionally cached
at each router along the path. In-network caching makes it difficult to enforce
access control policies on sensitive content outside of the producer since
routers only use interest information for forwarding decisions. To that end, we
propose an Interest-Based Access Control (IBAC) scheme that enables access
control enforcement using only information contained in interest messages,
i.e., by making sensitive content names unpredictable to unauthorized parties.
Our IBAC scheme supports both hash- and encryption-based name obfuscation. We
address the problem of interest replay attacks by formulating a mutual trust
framework between producers and consumers that enables routers to perform
authorization checks when satisfying interests from their cache. We assess the
computational, storage, and bandwidth overhead of each IBAC variant. Our design
is flexible and allows producers to arbitrarily specify and enforce any type of
access control on content, without having to deal with the problems of content
encryption and key distribution. This is the first comprehensive design for CCN
access control using only information contained in interest messages.
