  Information-Centric Networks (ICN) are promising alternatives to current
Internet architecture since the Internet struggles with a number of issues such
as scalability, mobility and security. ICN offers a number of potential
benefits including reduced congestion and enhanced delivery performance by
employing content caching, simpler network configurations and stronger security
for the content. Named Data Networking (NDN), an instance of the ICN, enables
content delivery instead of host-centric approaches by naming data rather than
the host. In order to make NDN practical in the real world, the challenging
issues of content security need to be addressed. In this article, we examine
the architecture, content security as well as possible solutions to these
issues of NDN, with a special focus on content integrity and provenance. We
propose a variety of digital signature schemes to achieve the data integrity
and origin authentication in NDN for various applications, which include
cost-effective signatures, privacy-preserving signatures, network coding
signatures, and post-quantum signatures. We also present the speed-up
techniques in generating signatures and verifying signatures such as
pre-computation, batch verification and server-aided verification to reduce the
computational cost of the producers and receivers in NDN. A number of
certificate-free trust management approaches and possible adoptions in NDN are
investigated.
