Hyperledger Fabric Model - Hyperledger Fabric模型

This section outlines the key design features woven into Hyperledger Fabric that fulfill its promise of a comprehensive, yet customizable, enterprise blockchain solution:

本节概述了编入Hyperledger Fabric的关键设计特性，实现了对全面又可定制的企业区块链解决方案的承诺：

• Assets - 资产 — Asset definitions enable the exchange of almost anything with monetary value over the network, from whole foods to antique cars to currency futures. 资产是可以通过网络交换几乎任何具有货币价值的东西，从所有食品、到古董车、到货币期货。
• Chaincode - 链码 — Chaincode execution is partitioned from transaction ordering, limiting the required levels of trust and verification across node types, and optimizing network scalability and performance. 链码执行与交易排序分开，限制了跨节点类型所需的信任和验证级别，并优化了网络可扩展性和性能。
• Ledger Features - 账本特征 — The immutable, shared ledger encodes the entire transaction history for each channel, and includes SQL-like query capability for efficient auditing and dispute resolution. 不可变的共享账本为每个通道编码整个交易历史记录，并包括类似SQL的查询功能，以便高效审计和解决争议。
• Privacy - 隐私 — Channels and private data collections enable private and confidential multi-lateral transactions that are usually required by competing businesses and regulated industries that exchange assets on a common network. 通道和私有数据收集实现了私密且机密的多边交易，这些交易通常是在共同网络上交换资产的竞争企业和受监管行业所要求的。
• Security & Membership Services - 安全和成员服务 — Permissioned membership provides a trusted blockchain network, where participants know that all transactions can be detected and traced by authorized regulators and auditors. 许可成员资格提供可信的区块链网络，参与者知道所有交易都可以由授权的监管机构和审计员检测和跟踪。
• Consensus - 共识 — A unique approach to consensus enables the flexibility and scalability needed for the enterprise. 达成共识的独特方法可实现企业所需的灵活性和可扩展性。

Assets - 资产

Assets can range from the tangible (real estate and hardware) to the intangible (contracts and intellectual property). Hyperledger Fabric provides the ability to modify assets using chaincode transactions.

资产的范围可以从有形（房地产和硬件）到无形资产（合同和知识产权）。Hyperledger Fabric提供使用链码交易修改资产的功能。

Assets are represented in Hyperledger Fabric as a collection of key-value pairs, with state changes recorded as transactions on a Channel - 通道 ledger. Assets can be represented in binary and/or JSON form.

资产在Hyperledger Fabric中表示为键值对的集合，状态更改记录为 Channel - 通道 账本上的交易。资产可以用二进制和/或JSON格式表示。

You can easily define and use assets in your Hyperledger Fabric applications using the Hyperledger Composer tool.

您可以使用 Hyperledger Composer 工具在Hyperledger Fabric应用程序中轻松定义和使用资产。

Chaincode - 链码

Chaincode is software defining an asset or assets, and the transaction instructions for modifying the asset(s); in other words, it’s the business logic. Chaincode enforces the rules for reading or altering key-value pairs or other state database information. Chaincode functions execute against the ledger’s current state database and are initiated through a transaction proposal. Chaincode execution results in a set of key-value writes (write set) that can be submitted to the network and applied to the ledger on all peers.

链码是定义单项或多项资产的软件，还能修改资产的交易指令；换句话说，它是业务逻辑。链码强制执行读取或更改键值对或其他状态数据库信息的规则。链码函数针对账本的当前状态数据库执行，并通过交易提议启动。链码执行导致一组键值写入（写入集），其可提交给网络并应用于所有节点的账本。

Ledger Features - 账本特征

The ledger is the sequenced, tamper-resistant record of all state transitions in the fabric. State transitions are a result of chaincode invocations (‘transactions’) submitted by participating parties. Each transaction results in a set of asset key-value pairs that are committed to the ledger as creates, updates, or deletes.

账本是Fabirc中所有状态转换的依序防篡改记录。状态转换是参与方提交的链码调用（“交易”）的结果。每个交易都会生成一组资产键值对，这些键值对以创建、更新或删除形式提交到账本。

The ledger is comprised of a blockchain (‘chain’) to store the immutable, sequenced record in blocks, as well as a state database to maintain current fabric state. There is one ledger per channel. Each peer maintains a copy of the ledger for each channel of which they are a member.

账本由区块链（“链”）组成，用于以区块的形式存储不可变的顺序记录，以及用于维护当前fabirc状态的状态数据库。每个通道有一个账本。每个节点为其所属的每个通道维护一个账本的副本。

Some features of a Fabric ledger:

Fabric账本的一些功能： - Query and update ledger using key-based lookups, range queries, and composite key queries - 使用基于密钥的查找，范围查询和组合密钥查询来查询和更新账本 - Read-only queries using a rich query language (if using CouchDB as state database) - 使用丰富查询语言的只读查询（如果使用CouchDB作为状态数据库） - Read-only history queries — Query ledger history for a key, enabling data provenance scenarios - 只读历史记录查询——查询密钥的账本历史记录，启用数据溯源方案 - Transactions consist of the versions of keys/values that were read in chaincode (read set) and keys/values that were written in chaincode (write set) - 交易包括以链码（读取集）读取的键/值的版本以及以链码（写入集）编写的键/值 - Transactions contain signatures of every endorsing peer and are submitted to ordering service - 交易包含每个背书节点的签名，并提交给排序服务 - Transactions are ordered into blocks and are “delivered” from an ordering service to peers on a channel - 交易按顺序排列到区块上，并从排序服务“交付”到通道上的节点 - Peers validate transactions against endorsement policies and enforce the policies - 节点根据背书策略验证交易并执行政策 - Prior to appending a block, a versioning check is performed to ensure that states for assets that were read have not changed since chaincode execution time - 在附加区块之前，执行版本控制检查以确保自链码执行时间以来读取的资产的状态未发生更改 - There is immutability once a transaction is validated and committed - 一旦交易被验证并提交，就存在不变性 - A channel’s ledger contains a configuration block defining policies, access control lists, and other pertinent information - 通道的账本包含定义策略，访问控制列表和其他相关信息的配置区块 - Channels contain Membership Service Provider - 成员服务提供者 instances allowing for crypto materials to be derived from different certificate authorities - 通道包含 Membership Service Provider - 成员服务提供者 的程序实例，允许从不同的证书颁发机构派生加密材料

See the Ledger - 账本 topic for a deeper dive on the databases, storage structure, and “query-ability.”

Privacy - 隐私

Hyperledger Fabric employs an immutable ledger on a per-channel basis, as well as chaincode that can manipulate and modify the current state of assets (i.e. update key-value pairs). A ledger exists in the scope of a channel — it can be shared across the entire network (assuming every participant is operating on one common channel) — or it can be privatized to include only a specific set of participants.

Hyperledger Fabric在每个通道的基础上使用不可变的账本，以及可以操纵和修改资产的当前状态（即更新键值对）的链码。账本存在于通道范围内 - 它可以在整个网络中共享（假设每个参与者在一个公共渠道上运营） - 或者它可以私有化以仅包括一组特定的参与者。

In the latter scenario, these participants would create a separate channel and thereby isolate/segregate their transactions and ledger. In order to solve scenarios that want to bridge the gap between total transparency and privacy, chaincode can be installed only on peers that need to access the asset states to perform reads and writes (in other words, if a chaincode is not installed on a peer, it will not be able to properly interface with the ledger).

在后一种情况下，这些参与者将创建一个单独的通道，从而隔离他们的交易和账本。为了解决想要弥合总透明度和隐私之间差距的场景，可以仅在需要访问资产状态以执行读取和写入的节点上安装链码（换句话说，如果未在节点上安装链码，它将无法与账本正确连接）。

When a subset of organizations on that channel need to keep their transaction data confidential, a private data collection (collection) is used to segregate this data in a private database, logically separate from the channel ledger, accessible only to the authorized subset of organizations.

当该通道上的组织子集需要保密其交易数据时，私有数据集合用于将此数据隔离在私有数据库中，在逻辑上与通道账本分开，只能由授权的组织子集访问。

Thus, channels keep transactions private from the broader network whereas collections keep data private between subsets of organizations on the channel.

因此，通道将交易保持从更广泛的网络私有，而集合使数据在通道上的组织的子集之间保持私有。

To further obfuscate the data, values within chaincode can be encrypted (in part or in total) using common cryptographic algorithms such as AES before sending transactions to the ordering service and appending blocks to the ledger. Once encrypted data has been written to the ledger, it can be decrypted only by a user in possession of the corresponding key that was used to generate the cipher text. For further details on chaincode encryption, see the Chaincode for Developers topic.

为了进一步模糊数据，在将交易发送到排序服务并将区块附加到账本之前，可以使用诸如AES之类的公共加密算法对链码内的值进行加密（部分或全部）。一旦加密数据被写入账本，它就只能由拥有用于生成密文的相应密钥的用户解密。有关链码加密的更多详细信息，请参阅 Chaincode for Developers 主题。

See the Private Data - 私有数据 topic for more details on how to achieve privacy on your blockchain network.

有关如何在区区块链网络上实现隐私的更多详细信息，请参阅 Private Data - 私有数据 主题。

Security & Membership Services - 安全和成员服务

Hyperledger Fabric underpins a transactional network where all participants have known identities. Public Key Infrastructure is used to generate cryptographic certificates which are tied to organizations, network components, and end users or client applications. As a result, data access control can be manipulated and governed on the broader network and on channel levels. This “permissioned” notion of Hyperledger Fabric, coupled with the existence and capabilities of channels, helps address scenarios where privacy and confidentiality are paramount concerns.

Hyperledger Fabric支持交易网络，所有参与者都拥有已知身份。公钥基础结构用于生成与组织，网络组件以及终端用户或客户端应用程序相关联的加密证书。因此，可以在更广泛的网络和通道级别上操纵和管理数据访问控制。Hyperledger Fabric的这种“许可”概念，加上通道的存在和功能，有助于解决隐私和机密性是最重要的问题。

See the Membership Service Providers (MSP) topic to better understand cryptographic implementations, and the sign, verify, authenticate approach used in Hyperledger Fabric.

请参阅 Membership Service Providers (MSP) 主题，以更好地了解加密实现，以及Hyperledger Fabric中使用的签名，确认，身份验证方法。

Consensus - 共识

In distributed ledger technology, consensus has recently become synonymous with a specific algorithm, within a single function. However, consensus encompasses more than simply agreeing upon the order of transactions, and this differentiation is highlighted in Hyperledger Fabric through its fundamental role in the entire transaction flow, from proposal and endorsement, to ordering, validation and commitment. In a nutshell, consensus is defined as the full-circle verification of the correctness of a set of transactions comprising a block.

最近，在分布式账本技术中，共识已成为单个函数内特定算法的同义词。然而，共识不仅包括简单地就交易顺序达成一致，而且Hyperledger Fabric通过其在整个交易流程中的基本角色，从提案和背书，到排序，验证和提交，突出了这种区别。简而言之，共识被定义为包含区块的一组交易的正确性的全圆验证。

Consensus is achieved ultimately when the order and results of a block’s transactions have met the explicit policy criteria checks. These checks and balances take place during the lifecycle of a transaction, and include the usage of endorsement policies to dictate which specific members must endorse a certain transaction class, as well as system chaincodes to ensure that these policies are enforced and upheld. Prior to commitment, the peers will employ these system chaincodes to make sure that enough endorsements are present, and that they were derived from the appropriate entities. Moreover, a versioning check will take place during which the current state of the ledger is agreed or consented upon, before any blocks containing transactions are appended to the ledger. This final check provides protection against double spend operations and other threats that might compromise data integrity, and allows for functions to be executed against non-static variables.

当区块的交易的订单和结果满足明确的政策标准检查时，最终会达成共识。这些检查和平衡发生在交易的生命周期中，并包括使用背书策略来指定哪些特定成员必须背书某个交易类，以及系统链码以确保强制执行和维护这些策略。在提交之前，节点将使用这些系统链码来确保存在足够的背书，并且它们来自适当的实体。此外，在包含交易的任何区块附加到账本之前，将进行版本控制检查，在此期间，账本的当前状态为同意。此最终检查可防止双重花费操作和可能危及数据完整性的其他威胁，并允许针对非静态变量执行功能。

In addition to the multitude of endorsement, validity and versioning checks that take place, there are also ongoing identity verifications happening in all directions of the transaction flow. Access control lists are implemented on hierarchical layers of the network (ordering service down to channels), and payloads are repeatedly signed, verified and authenticated as a transaction proposal passes through the different architectural components. To conclude, consensus is not merely limited to the agreed upon order of a batch of transactions; rather, it is an overarching characterization that is achieved as a byproduct of the ongoing verifications that take place during a transaction’s journey from proposal to commitment.

除了发生的大量背书，验证和版本检查之外，交易流的所有方向上还发生着持续的身份验证。访问控制列表在网络的分层上实现（排序服务到通道），并且当交易提议通过不同的体系结构组件时，有效负载被重复签名，确认和验证。总而言之，共识不仅限于一批交易的商定订单；相反，它是一种总体特征，是在交易从提案到背书的过程中进行的持续验证的副产品。

Check out the Transaction Flow diagram for a visual representation of consensus.

查看 Transaction Flow 以获得共识的直观表示。