  In recent years, there is an emerging trend that some computing services are
moving from cloud to the edge of the networks. Compared to cloud computing,
edge computing can provide services with faster response, lower expense, and
more security. The massive idle computing resources closing to the edge also
enhance the deployment of edge services. Instead of using cloud services from
some primary providers, edge computing provides people with a great chance to
actively join the market of computing resources. However, edge computing also
has some critical impediments that we have to overcome.
  In this paper, we design an edge computing service platform that can receive
and distribute the computing resources from the end-users in a decentralized
way. Without centralized trade control, we propose a novel hierarchical smart
contract-based decentralized technique to establish the trading trust among
users and provide flexible smart contract interfaces to satisfy users. Our
system also considers and resolves a variety of security and privacy challenges
when utilizing the encryption and distributed access control mechanism. We
implement our system and conduct extensive experiments to show the feasibility
and effectiveness of our proposed system.
