A Novel Enhanced Lightweight Node for Blockchain Blockchain is a single linked list and its data volume grows endlessly. Each node in the Blockchain network keeps the entire data, which not only waste storage, but also requires a vast amount of computation which is wasteful and scales poorly. The SPV (simplified payment verification) node simplifies node storage, but decentralization, the most important feature of Blockchain, is compromised. To address the issue, this paper proposes a novel enhanced lightweight node called ESPV (Enhanced SPV) based on the analysis of the characteristics of Blockchain data. ESPV nodes label blocks as new and old, and keep all the new blocks while storing partial old blocks according their capacity. A hierarchical block partition routing table is established to ensure data availability when ESPV nodes access old blocks they do not have. An ESPV node has all the functions of a full node to ensure the decentralization and stability of a Blockchain system.

A New Structure of Blockchain to Simplify the Verification. Blockchain is first introduced in Bitcoin and has good performance in cryptocurrencies. With the growth of chain, the height of blockchain in Bitcoin has reached five hundred thousand, and the entire capacity of chain is more than 500 GB. If a light node wants to verify a transaction, it has to spend nearly one week to download the data of whole chain with download rate of 1 MBs, which seriously hinders the usage of blockchain. In order to resolve this problem, checkpoint is used to reduce the capacity of data, but this centralized scheme obviously violates the decentralization of blockchain. Other schemes are proposed will change the structure of blockchain may suffer the risk that adversary can fork a blockchain to cheat the light nodes. In this paper, we propose a novel blockchain architecture, which simplifies the verification in blockchain and is compatible with most consensus mechanism. We append backlinks in some blocks, such that blocks not only look like a chain but also like a binary tree. We also introduce a challenge mechanism for against the forking attack on light nodes.