  Blockchain is a merging technology for decentralized management and data
security, which was first introduced as the core technology of cryptocurrency,
e.g., Bitcoin. Since the first success in financial sector, blockchain has
shown great potentials in various domains, e.g., internet of things and mobile
networks. In this paper, we propose a novel blockchain-based architecture for
content delivery networks (B-CDN), which exploits the advances of the
blockchain technology to provide a decentralized and secure platform to connect
content providers (CPs) with users. On one hand, the proposed B-CDN will
leverage the registration and subscription of the users to different CPs, while
guaranteeing the user privacy thanks to virtual identity provided by the
blockchain network. On the other hand, the B-CDN creates a public immutable
database of the requested contents (from all CPs), based on which each CP can
better evaluate the user preference on its contents. The benefits of B-CDN are
demonstrated via an edge-caching application, in which a feature-based caching
algorithm is proposed for all CPs. The proposed caching algorithm is verified
with the realistic Movielens dataset. A win-win relation between the CPs and
users is observed, where the B-CDN improves user quality of experience and
reduces cost of delivering content for the CPs.
