DLCP: A protocol for securing light client operation in blockchains

Abstract

In blockchain, full nodes (FNs) are peers that store and verify entire chains of transactions, and light clients (LCs) are those which outsource chain verification to FNs (as they lack computing resources required to do so). In general, LCs perform simpler verification protocols, e.g. Simple Payment Verification (SPV), by offloading the execution of blockchain operations to FNs. To cope with byzantine faults (like malicious behavior), a current approach for blockchain transaction verification is requiring that LCs outsource their requests to multiple FNs, and compare received results. This approach, however, requires that LCs establish secure connections to each FN, which leads to client-side complexity and slower verification. To tackle this issue, we propose Distributed Lightweight Client Protocol (DLCP), a protocol for secure verification in blockchain. In summary, DLCP requires LCs to encrypt a request once, allowing a pre-determined set of FNs to access and process it. Through DLCP, LCs become able to verify whether FNs have agreed on the operation outcome. From some preliminary evaluation, we observed that DLCP decreased computing and communication overhead in LCs, while providing lower latency.