Velocity: Scalability Improvements in Block Propagation Through Rateless Erasure Coding

Blockchain technology and other distributed ledger systems fill an important role in resilient data storage and publication. However, their normally-decentralized methods also bring unique challenges distinct from more traditional approaches. One lies in the replication of data between participating nodes; since no individual node is more trusted than any other, each node maintains its own copy of the entire ledger for the purposes of validating new transactions. Improving how this information is stored and more importantly, how it propagates across the network, are open research questions. In this work, we propose Velocity, a novel block propagation approach based on fountain codes, allowing for better decentralized delivery of blocks and reduced network bottlenecks without sacrificing the security guarantees of the blockchain ledger itself. We also provide an assessment of economic incentives and their impact on participant behavior, showing that the proposed approach is financially beneficial to rational actors. We conclude by showing experimentally that this approach permits for the mining of even larger blocks, thereby increasing transaction throughput of the system compared to existing state of the art methods.