Abstract
Content compliance validation provides a formal and secure procedure for applications (like emails or social networks) to determine how an intended action can be carried out. By conducting the validation against predefined policies, only compliant content is allowed to be delivered. Unfortunately, current solutions suffer from multiple issues such as intensive server-side overheads, intransparency and centralization.
To address these drawbacks, we propose DeCCV, the first decentralized content compliance validation protocol for real-world applications. In our work, the application requires to transparently declare its validation policies (Policy(VAL)(Cont)) on the blockchain. Meanwhile, we outsource the resource-intensive validations to multiple decentralized off-chain validation nodes, which verify user's content locally and issue the proofs (signatures) accordingly. Therefore, the burden of server-end workloads is minimized to merely signature-based verification. Moreover, a dedicated incentive mechanism is proposed to motivate high accountability of validation participants. DeCCV is platform-friendly that can be compatible with most real-world applications. We fully implement DeCCV for Gmail, Twitter and Dropbox to show its versatility.