Adventures of a Light Blockchain Protocol in a Forest of Transactions: A Subset of a Story

Abstract

The Ethereum blockchain is one of the most popular permissionless blockchains. A consequence of its popularity has been the growth of processing and data storage requirements for any node participating in the Ethereum blockchain network. For constrained devices such requirements are often infeasible to meet. To cater for such nodes, a so-called light protocol has been proposed for Ethereum where the responsibility of maintaining a correct state representation is delegated to light protocol servers. Previous research has identified dependence on external state management as a potential security vulnerability that exclusively impacts light nodes. Although a simple mitigation strategy is available, it comes at the expense of increased latency. In this work, we propose a new Ethereum node type, which we call a subset node, as an extension of the light protocol. Our proposal allows subset nodes to gain a lower latency than a pure light node with comparable or even higher security assurances by tracking and evaluating only a subset of all of the transactions issued on the blockchain. We provide a formal proof on the correctness of the blockchain state used by the subset node under the proposed model. To evaluate the practical feasibility of the subset node model, we analyze one year of historical transaction data from Ethereum, and demonstrate that a subset node tracking the state of a single account can achieve a significant reduction in storage and computational requirements when compared to a full node.

ISTVP: Independent single transaction verification protocol for light node using fraud proofs without collaborator

“…These nodes have more storage than a typical light node but significantly less than a full node. In [10], a scheme for an Ethereum light node called a subset node is proposed. The subset node is an extension of the light node protocol, with the difference that the node locally computes the state of the entire distributed network account.…”

“…To enhance the security of light nodes and mitigate attacks, various approaches have been proposed, such as Fraud Proof [17,18], Super-light clients [11,12,13], block-specific secure light node schemes [9,10], and block compression schemes [14,15,16]. Among them, Fraud Proof plays a pivotal role in securing transactions.…”