An Enhanced Lightweight Node Model For UTXO Type Blockchain

The Blockchain adopts a chain append mode similar to the log form,which cannot be interrupted,changed,or deleted,but can only increase data.With the accumulation of time,the data volume of the system will increase linearly,but the storage space of the nodes is limited,so the storage scalability of the system is an inevitable problem.The Blockchain system uses a completely redundant storage method.Each node saves a copy of data,which causes a huge waste of storage space for the entire system.In order to allow hardware with less storage space to use the Blockchain system,the Bitcoin white paper proposes a SPV(simplified payment verification)node model.Nodes only need to save the data in the block header,which greatly reduces the node's need for storage space,but with its popularity,the number of full nodes will decrease,and the pressure will increase,reducing the degree of decentralization of the entire system.Because it does not have all the block data,it cannot verify transactions,it can only perform payment verification,and there are security risks such as witch attacks and denial of service attacks.In view of the above problems,this paper analyzes the data of Bitcoin blocks and network nodes,and proposes a fully functional blockchain enhanced lightweight node model ESPV(Enhanced SPV)suitable for UTXO type.Using the knowledge of data management,ESPV marks the blocks in the system as new and old blocks,and uses different storage management strategies for different block types.The new block is stored in a completely redundant manner(one copy is saved for each node),so as to build a UTXO(unspent transaction output)library for transaction verification.In this way,ESPV has a verification transaction(mining)with a small amount of storage space.The old blocks are stored in shards,distributed among the nodes of the network,and accessed through the designed hierarchical block partition routing table.This reduces the redundancy of the system while ensuring data availability and reliability,thereby reducing Waste of storage space by the system.ESPV nodes have complete node functions,enhance peer-to-peer relationships,maintaining the decentralization,an important feature of the Blockchain,and increase system security and stability.This article uses the existing block and node information of Bitcoin as a data set for processing analysis in a Linux system with 16 GB of memory.The experimental results show that ESPV is applicable to the entire life cycle of the system,the transaction verification rate can be guaranteed above 80%,and the system's data volume and annual growth are only one-tenth of the full node,and the system's data availability and Reliability is guaranteed.