CoVer: Collaborative Light-Node-Only Verification and Data Availability for Blockchains
This addresses security vulnerabilities for resource-limited clients in blockchain systems, offering a novel solution for decentralized verification.
The paper tackles the problem of high resource costs for blockchain validation by proposing CoVer, a decentralized protocol that enables light nodes to collaboratively verify blocks securely without relying on full nodes, achieving sublinear scaling in computation, communication, and storage relative to block size.
Validating a blockchain incurs heavy computation, communication, and storage costs. As a result, clients with limited resources, called light nodes, cannot verify transactions independently and must trust full nodes, making them vulnerable to security attacks. Motivated by this problem, we ask a fundamental question: can light nodes securely validate without any full nodes? We answer affirmatively by proposing CoVer, a decentralized protocol that allows a group of light nodes to collaboratively verify blocks even under a dishonest majority, achieving the same level of security for block validation as full nodes while only requiring a fraction of the work. In particular, work per node scales down proportionally with the number of participants (up to a log factor), resulting in computation, communication, and storage requirements that are sublinear in block size. Our main contributions are light-node-only protocols for fraud proofs and data availability.