区块链学习系列：What is a Bitcoin Node?

KEY HIGHLIGHTS

---- A Bitcoin node stores and verifies each block in the blockchain. Nodes form a network by connecting and sharing blocks and transactions with one another.
（比特币节点存储和验证区块链中的每个块。 节点通过相互连接和共享块和交易来形成一个网络）

---- A node allows a user to verify bitcoin balances without a trusted third party.
（节点允许用户在没有受信任的第三方的情况下验证比特币余额）

---- By running a node, a user is capable of enforcing the rules of the network, ensuring that they are not being deceived and that other parties cannot maliciously change Bitcoin’s ruleset.
（通过运行一个节点，用户能够执行网络规则，确保他们不会被欺骗，并且其他方不能恶意更改比特币的规则集）

Bitcoin is a peer-to-peer currency that is regulated by a network of nodes. A node is simply a computer that runs the Bitcoin software. Bitcoin nodes send and receive transactions with other nodes in the network and verify their validity. Bitcoin nodes cooperate with Bitcoin miners to maintain the integrity of the system.
（比特币是一种由节点网络监管的点对点货币。 节点只是一台运行比特币软件的计算机。 比特币节点与网络中的其他节点发送和接收交易并验证其有效性。 比特币节点与比特币矿工合作以维护系统的完整性）

First, nodes broadcast and relay transactions to other nodes and miners. Miners batch these transactions into blocks and publish those blocks to the blockchain, validating the transactions. Nodes receive these blocks, share them amongst one another, and verify that the miners are following the rules of the network. When a node receives a new transaction or block, it relays it to its peers, so that all nodes and miners can remain in sync and maintain identical blockchains.
（首先，节点向其他节点和矿工广播和中继交易。 矿工将这些交易打包成区块并将这些区块发布到区块链，从而验证交易。 节点接收这些块，彼此共享它们，并验证矿工是否遵守网络规则。 当一个节点收到一个新的交易或区块时，它会将其转发给它的对等节点，以便所有节点和矿工可以保持同步并维护相同的区块链）

Types of Bitcoin Nodes Full Node

A full node’s main function is to independently verify the state of the Bitcoin blockchain. It does so by downloading every block and transaction and checking them against Bitcoin’s consensus rules. If a transaction or block violates one of Bitcoin’s consensus rules, a full node will automatically reject it.
（全节点的主要功能是独立验证比特币区块链的状态。 它通过下载每个区块和交易并根据比特币的共识规则检查它们来做到这一点。 如果交易或区块违反了比特币的共识规则之一，全节点将自动拒绝它）

Lightweight / SPV client

A lightweight or Simplified Payment Verification client, are similar to full nodes in that they can verify whether transactions were included in a block. However, light nodes do not verify and validate all of the network’s transactions and do not store a copy of the blockchain.
（轻量级或简化支付验证客户端类似于完整节点，因为它们可以验证交易是否包含在块中。 但是，轻节点不会验证和验证网络的所有交易，也不会存储区块链的副本。）

Because light nodes don’t process large amounts of data through the network, they are much cheaper to maintain. For this reason, they were historically used in mobile Bitcoin wallet but are quite rare today.
（因为轻节点不通过网络处理大量数据，所以它们的维护成本要低得多。 出于这个原因，它们在历史上被用于移动比特币钱包，但今天非常罕见。）

Why Run a Full Node?

Users run a Bitcoin full node for many reasons. Primarily, it allows a user to independently verify the state of the Bitcoin network. As a result, a user can:
（用户出于多种原因运行比特币全节点。 首先，它允许用户独立验证比特币网络的状态。 因此，用户可以：）

Verify Bitcoin’s supply. Users can independently verify the state of the Bitcoin network.
（验证比特币的供应。 用户可以独立验证比特币网络的状态。）
Prevent the double spending of bitcoin. A node will automatically reject bitcoin that has been spent before.
（防止比特币的双重支出。 一个节点会自动拒绝之前已经使用过的比特币）
Use Bitcoin without third parties. A node allows users to broadcast and verify their own transactions rather than relying on a third party.
（在没有第三方的情况下使用比特币。 节点允许用户广播和验证他们自己的交易，而不是依赖第三方）
Another motivation for running a full node is to make the Bitcoin network more robust. As more nodes exist to fully validate transactions, the network becomes more resistant to certain types of attacks. Distributed, fully-functioning nodes are central to Bitcoin’s decentralized, peer-to-peer architecture and help keep the network secure.

In short, Bitcoin nodes are the central nervous system of the Bitcoin network. They broadcast, verify, and store transactions. They act both as gateways to the network and an information superhighway to relay network data to all participants.
（运行全节点的另一个动机是让比特币网络更加健壮。 随着越来越多的节点存在来完全验证交易，网络对某些类型的攻击更具抵抗力。 分布式、功能齐全的节点是比特币去中心化、点对点架构的核心，有助于保持网络安全

简而言之，比特币节点是比特币网络的中枢神经系统。 他们广播、验证和存储交易。 它们既充当网络的网关，又充当将网络数据中继给所有参与者的信息高速公路）