重磅首发 | R3 Corda项目非技术白皮书(中英翻译稿) - 前沿洞察...

来自 : rdc.hundsun.com/portal/article 发布时间：2021-03-26

原文：https://r3cev.com/blog/2016/8/24/the-corda-non-technical-whitepaper

作者：理查德.詹都.布朗，詹姆斯.卡莱尔，伊恩格里格，迈克.赫恩

翻译：魏帅，杨建勇，平风，李庆涛

校对：www.51chain.net

2016年8月24日R3（世界顶级金融区块链联盟）在众多知名金融机构一起经历近一年的区块链金融行业应用验证之后，在其官博上发布Corda项目非技术白皮书，描述了金融机构需要什么样的区块链技术，以及R3Corda平台的愿景，宣称目前尚没有能匹配金融需求的区块链平台。但R3相信：通过建立和完善一个记录金融事务和处理商业逻辑的共享平台，为金融组织间（尤其包括但不限于交易后的清算结算场景）的经济来往创造条件：一个具有权威性可纪录企业间所有协议的唯一全局逻辑账本，这种架构将会为业界建立全新的共享平台，在平台上，新加入者和第三方可以竞相发布创新式的产品和服务。恒生开发者社区旗下区块链园地51chain第一时间翻译R3 Corda的这份白皮书，分享给大家。

摘要：

A distributed ledger made up ofmutually distrusting nodes would allow for a single global database thatrecords the state of deals and obligations between institutions and people.This would eliminate much of the manual, time consuming effort currentlyrequired to keep disparate ledgers synchronised with each other. It would alsoallow for greater levels of code sharing than presently used in the financialindustry, reducing the cost of financial services for everyone. We presentCorda, a platform which is designed to achieve these goals. This paper providesa high level introduction intended for the general reader. A forthcomingtechnical white paper elaborates on the design and fundamental architectural decisions.

由相互不信任的节点所组成的分布式账本，将被考虑组成一个全局性数据库，用于存储金融机构和个人之间交易和债务的状态。这将消除大量目前需要手工并且耗时的工作，用以保持各个独立账本之间的数据同步。也将被考虑用作比现行金融业更高水平的代码共享，以降低人们的金融服务成本。我们推出Corda，就是一个解决这些问题的平台。这篇文章为普通大众提供高水平的介绍，接下来的技术白皮书将会详细阐述其设计理念和基础框架决策。

1- 引言

At R3, we believe that distributed ledger technology has thepotential to transform the financial services industry to the benefit of itsclients and participant firms alike. We envision a future where financialagreements are recorded and automatically managed without error, where anybodycan transact seamlessly for any contractual purpose without friction. Webelieve markets will move towards models where parties to financial agreementsrecord them once and collaborate to maintain accurate, shared records of theseagreements. Duplications, reconciliations, failed matches and breaks will bethings of the past. Isolated islands of asset representations will be no more.

We aspire to define a shared ledger fabric for financial servicesuse-cases that can be deployed within existing legal frameworks and whichrelies on proven technologies. Our philosophy can be broken down into threecategories: engineering for the requirements of institutions, a focus onnon-functional requirements, and extensibility.

This paper introduces the design features of the Corda platformwhich we believe make it an attractive choice for regulated financialinstitutions.

在R3，我们相信分布式账本技术将会使得不仅仅是金融服务行业还有行业内的客户和相关公司获益匪浅。我们的愿景是：金融协议将会被存储并且自动精确管理，每个人可以无误地处理任何契约和合约。我们相信趋势将会是：参与者达成的合约一旦被记录，就可以永远被准确无误地持有和共享。重复、调解、匹配失败和损坏都将成为历史，以资产为代表的孤岛将不再出现。

我们渴望依赖已经被证明的技术，在现有的法律框架内，为金融服务用例创建一个共享账本架构。我们的观点可以分为以下三类：满足机构的工程需要、关注非功能性的需求、可扩展性。

本文介绍Corda平台的设计特性，我们相信这个平台对金融机构会是非常不错的选择。

2 -背景

Banks were amongst the earliest adopters of information technologyand, contrary to popular belief, they have done a good job in automatingpreviously manual processes and in digitizing previously physical processes.However, there are significant opportunities to improve the cost and efficiencyof the architectures that emerged.

银行敢于突破传统思维，较早地利用信息技术，将手工处理精确地自动化，将物理处理精确地数字化。然而，现在是时候改善由之带来的高成本和复杂架构了。

In particular, each financial institution maintains its ownledgers, which record that firm’s view of its agreements and positions withrespect to its customer set and its counterparts. Its counterparts, in turn,maintain their views. This duplication can lead to inconsistencies, and itdrives a need for costlymatching, reconciliation and fixing of errors by and among the various partiesto a transaction. To the extent that differences remain between two firms, viewsof the same transaction, this is also a source of risk, some of it potentially systemic.

值得一提的是，每个金融机构都以自己的角度维护着记录客户群和合作单位协议、地位的账本。同样，合作单位也以自己的角度维护着这样一个账本。角度不同导致的账本不一致性，必然会带来机构之间对账、核算、纠错的巨大耗费。对同一笔交易，双方认知存在差异，这也是一个风险，并且可能是系统性的风险。

A plurality of financial institutions drives competition andchoice but the plurality of technology platforms upon which they rely drivescomplexity and creates operational risk. However, until recently, this wasunavoidable: except for centralised market infrastructures, there were few effective ways toconsolidate technology across firms without also consolidating the firmsthemselves.

出于竞争需要，多数金融机构选择主流的、复杂的、会带来操作风险的技术平台，然而一直以来，风险不可避免，除非采用集中化的市场基础设施。由此看来，仅仅依靠合作公司提高技术而不提高自己的水平是行不通的。

Centralised market infrastructure utilities have gone some waytowards increasing the amount of data and business-logic sharing between firmsbut, over all, the degree of integration achieved in the realm of financialtransactions still lags far behind that which has been achieved in the realm ofinformation exchange since the advent of the web.

自从互联网出现以来，集中化市场设施正在不断增加机构间的共享数据、交易量和成本，金融交易领域的集成度仍然远远落后于信息交换领域。

We believethat the maturation of cryptographic techniques, exemplified in part by what iscommonly referred to as “blockchain technology”, provides a new opportunity:the possibility of authoritative systems of record that are securely sharedbetween firms. This vision provides the opportunity to transform the economicsof financial firms, particularly but not exclusively in post-trade services, byimplementing a new shared platform for the recording of financial events andprocessing of business logic: one where a single global logical ledger isauthoritative for all agreements between firms recorded on it. Thisarchitecture will define a new shared platform for the industry, upon whichincumbents, new entrants and third parties can compete to deliver innovativenew products and services.

我们相信加密技术的进步，比如典型的经常提及的区块链技术，提供了一个新的机遇：机构间安全地共享记录的权威性系统。这种愿景，通过建立和完善一个记录金融事务和处理商业逻辑的共享平台，为金融组织间（尤其包括但不限于交易后服务行业）的经济来往创造条件：一个具有权威性可纪录企业间所有协议的唯一全局逻辑账本。这种架构将会为业界建立全新的共享平台，在平台上，新加入者和第三方可以竞相发布创新式的产品和服务。

图1

Figure 1: Inthe diagram above, we show a progression from a world where parties to sharedfacts record and manage their own records, with associated discrepancies andduplications (“Bilateral - Reconciliation”)or one where parties delegate control and responsibility over criticalprocessing to centralized utilities (“Third Party/ Market Infrastructure”), to one where they collaborate tomaintain a shared record, assured to be consistent between them, consuming theservices of existing and new service providers and market infrastructure providerson an open and competitive basis (“Shared Ledger Vision”).

图1所示，我们展示了世界上的参与者如何共享和管理自己的纪录，可以通过处理相关的差异和副本（双边协商），也可以托管和依赖于关键的集中系统单元（第三方/市场基础架构），又或是共同维护一个共享的、确保一致性的纪录，并且开放又竞争地使用已有的和服务商新提供的服务和基础设施（共享账本愿景）。

We believethat the savings accruing from higher-quality data, fewer discrepancies andquicker agreement of details between firms will be significant. Moreover, deploymentof this common architecture across firms will define a new platform on whichexisting and new providers can compete to serve the needs of clients. Goingfurther, it is possible that such a platform will also find application withinfirms, where the problem of multiple systems recording details of the sametrades is also a major driver of cost and complexity.

我们相信，更高质量的数据、更少的差异和企业间更快地达成协议所带来的成本节约，将具有重大意义。此外，在公司间部署一个通用的架构将会诞生一个新的平台，通过这个平台，现有的和新加入的服务提供商可以充分竞争以服务客户。进一步说，在多个系统记录相同交易所导致成本和复杂性增加的情况下，这样的平台同样可能找到企业内部所需要的应用。

In thelong-term, one can envision a “global logical ledger” with which all economicactors will interact and which will allow any parties to record and manage agreementsamongst themselves in a secure, consistent, reliable, private and authoritativemanner. We say it is global in the sense that everybody sees the same data thatpertains to them and logical in the sense that the physical implementation maybe composed differently. Assuch, a possible end-state is one in which we have moved from authoritativesystems-of-record maintained within firms to global authoritativesystems-of-record sharedbetweenfirms.

长期来看，人们可以预想借助“全球逻辑账本”，使所有经济参与者充分互动，任何参与方均可通过一种安全、一致、可靠、私密和权威的方式，来记录和管理彼此之间的协议。之所以称之为全球，是因为呈现给每个人的数据都是一样的；之所以符合逻辑，是因为其物理方式的实现会有所差异。因此，可能的最终状态，将会是从企业内部维护的具有权威性的账本系统，发展到企业间可共享的具有全局权威性的账本系统。

3.1 End-State Principles终态原则

Principlesunderpinning a possible end-state using distributed ledger technology mayinclude:Factsrecorded by the ledger are, by contract, accepted as admissible evidence andlegally binding by all parties in any dispute.Facts recorded by the ledger are regarded asauthoritative rather than “shadows” of authoritative data held elsewhere,enabling settlement to take place directly across the platform.Once all parties to an agreement have assented,facts recorded on the ledger are final and immutable; errors and unwinds mustbe processed through a subsequent transaction. Firms will be under pressure toreengineer their internal processes to increase accuracy and quality.Any authorized actor may, in principle, connectdirectly to the ledger and use it to record agreements with its counterparts.No actor is compelled to deal with any other but we may see a decline in“tiered” or hierarchical market models.By promoting open standards and inclusive access,existing and new service providers can connect and compete to offer differentiatedservices, promoting choice and competition.The only parties who should have access to thedetails of a financial transaction are those parties themselves and others witha legitimate need to know.

如果使用分布式账本技术，终态原则包括：

按照合约记录在账本上的事实，无论有任何争议，都会被各方看作是有力的证据，并且具有法律约束力。记录在账本上的事实是具有权威性的，而非在别处取到的副本，因此直接通过平台更容易达成协议。参与方一旦达成协议，账本上的记录就是最终且不可更改的。更正错误或解约唯有通过一系列后续操作来实现，这将促使公司不得不通过严格的内控和流程来提高工作的准确性和质量标准。原则上，任何授权参与方，可以直连账本，并通过账本的副本来记录协议，不用考虑那些分级或者等级市场模型。通过提供开放式的标准和私密性的访问服务，已有的和新加入的服务提供商都可以提供差异化的服务，促进选择和竞争。唯一能访问金融交易内容的是参与方本人，和那些合法可见的人。

However, thevision encompasses the notion of interim states, such as those that focus firston the sharing only of business logic. This is intended to acknowledge thereality that today’s systems will be with us for the foreseeable future,requiring co-existence, integration and migration paths as a fundamental partof the solution design. These interim states can also deliver considerable valuewhilst legal and other non-technical implications of the longer-term vision areaddressed in parallel.

然而，这个愿景的最终实现需要一个过渡时期，比如最初只关注共享商业逻辑的参与方。现有的系统在可预见的未来将会一直存在，意识到这一点，在设计解决方案的时候就需要把现有系统的共存、集成、移植考虑进来。过渡时期照样可以带来可观的价值，尤其是当合法化和其他非技术性因素同长期的愿景处于并行的时候。

It should bestressed that the long-term vision of a global logical ledger is intended toset a direction of travel but that its realization may be in the form of amultiplicity of ledgers. Perhaps this will take the form of one ledger per assetclass which would be autonomous, loosely coupled, providing functionaland operational independence between different business services.

需要强调的是，我们的远期目标是实现一个全球逻辑账本，但是在实现上可能是多种形式的分类账本。或许表现为每种资产类型将会形成一个账本，在不同商业服务之间保持匿名、松散耦合，同时提供功能和操作上的独立。

Architecturaland strategic choices underpinning the vision include:

Recordsmanaged by this system will be accessible only to those actors with alegitimate interest in the assets and agreements they manage.The behavior of agreements managed by the systemwill be described in computer code that explicitly refers to and gains itslegitimacy from overarching legal prose.Support for contract code upgrades and explicitreference to dispute resolution procedures will be supported in order toprovide certainty in the presence of failed contracts. This is becausecontractual disputes can occur, even in automated settings, as a result of bothtechnical and human factors.Successful delivery of this vision will be throughreduction of cost, risk and regulatory burden (including capital, liquidity andoperational obligations) and through enabling of innovative new products andservices.To gain wide adoption across the financialcommunity, portions of the system must and will be open: open source, opendevelopment process, open standards.Although this vision talks in terms of a“platform” or “system”, our belief is that the design will actually bemulti-layered with different providers potentiallycompeting/collaborating to deliver different pieces. Readers should not assume that weenvisage a monolithic vertically integrated approach.The vision also includes the possibility thathigher-level layers of the stack can contain IP proprietary to individual firmsor groups.This system will operate under the assumption ofan adversarial security environment: the growing threat of cybercrime must betaken as a given.

支撑基础架构和战略选择的愿景包括：

只有那些授权管理或者资产利益相关的角色能够访问本系统管理的记录数据。系统管理的授权行为将会使用计算机代码来描述，这段代码必须获得基本法的合法授权。为了提供处理失败合约的确定性方法，本系统提供了对合约码升级的支持以及明确给出如何处理争议的参考。通过降低成本，风险和监管负担（包括资本，流动性和运作的义务），并通过实现创新的新产品和服务这一愿景就可以成功交付。为获得在整个金融社区的广泛应用和认可，本系统的部分必须公开并将要公开：开源，开放研发进程，开放标准。虽然本愿景使用了诸如：平台或者系统等词语，我们相信本系统在不同的提供者（不管他们是竞争关系还是合作关系）们提供发布各自的部分以让该系统实现多层模式的设计架构，读者不应该想象成我们把这个系统设计成了一个单片垂直整合的模式。对于参与建设的独立的公司或者组织来说他们也有愿景： 获得产品栈上处于高层级的分层所包含的IP资产。基于日益严重的网络犯罪和严峻的网络安全形式，本系统会采用高标准的安全设计来应对。

It is believedthat the fundamental inventions needed to deliver this vision already exist.These include, but are not limited to, robust cryptography, global communicationsnetworks, standards for the definition of financial instruments and effectivealgorithms to ensure consistency at a global scale.

据有人认为，支持这一愿景的基础性发明已经实现，包括但不限于：健壮的加密技术，全球通信网络，金融工具定义的标准化以及有效的全球范围一致性保证算法。

What makesthis vision possible today is that the recent popular interest in distributedledger and blockchain systems has created an environment in which such a visioncan be openly discussed and that a collaborative alliance through whichmultiple financial institutions can act together has been formed. It assumes anidentity infrastructure between the participants in the network but makes noassumption as to its sophistication or mode of operation. Regulatory engagementis a key element of the design process.

最近广受关注的分布式账本和区块链系统已经创造了一个使这一愿景能被公开讨论的环境，一些金融机构建立了合作联盟来推进和建设这些系统，这些都让这个愿景离实现越来越近。我们假设网络上的参与者之间有一种用来标识的基础构件但是至于这种构件的复杂度如何以及它的运作模式我们不关心。监管层的参与是设计过程的一个关键因素。

From ourrequirements analysis and assessment of existing distributed ledgerplatforms, we concluded that no existing platform met our needs. In essence,the threat models underpinning the designs of traditional distributed databaseswere unsuitable for our use-case of bringing mutually distrusting legalentities into consensus; and the architectures of existing blockchain systems wereunsuitable for our requirement of restricted and carefully specified datasharing at the level of individual legal agreements. As a result we designedand began development of Corda.

从我们的需求角度分析以及对现已存在的分布式账本平台的评估，我们得出结论：目前尚没有能匹配我们需求的平台。本质上来说，支撑传统分布式数据库系统设计的威胁模型并不适用于我们目前面临的状况：让互不信任的法律实体达成一致（其实就是说区块链技术可以做到交易可信赖而不需要第三方担保）。已存在的区块链系统架构也不适用于我们关于在个体法律协议层级的受限细分数据的共享这个应用场景。

所以我们设计并着手开发Corda平台。

4-Corda

Cordais a distributed ledger platform for recording and processing financial agreements,designed to implement the vision contained in this document.

Corda是一个用于记录和处理金融合约的分布式账本平台，我们设计它用来实现本文所描述的那些愿景。

The Cordaplatform supports smart contracts, matching the definition of Clack, Bakshi,Braine. 3 Our smart contract is an agreement whose executionis bothautomatableby computer code working with humaninput and control, and whose rights and obligations, as expressed in legalprose, are legallyenforceable. Thesmart contract links business logic and business data to associated legal prosein order to ensure that the financial agreements on the platform are rooted firmlyin law and can be enforced and that we have a clear path to follow in the eventof ambiguity, uncertainty or dispute.

Corda平台支持智能合约，符合Clack，Bakshi，Braine的定义。智能合约是由人工输入和控制共同协作的可自动执行计算机代码，其权利和义务也通过法律条文明确表述具有法律效力。智能合约把业务逻辑和业务数据关联到相关的法律条文上以保证平台上的金融合约能强力根植于法律上，这样当金融合约各方存在争议和不确定时，我们就能有一条清晰的路径能找到相关的法律依据。

4.1主要特性

Corda is specialized for use with regulated financialinstitutions. It is heavily inspired by blockchain systems, but without thedesign choices that make traditional blockchains inappropriate for manyfinancial scenarios.

Corda provides a framework to run smart contracts with these keyactivities and features:

Recording and managing theevolution of financial agreements and other shared data between two or moreidentifiable parties in a way that is grounded in existing legal constructs andcompatible with existing and emerging regulationChoreographing workflow between firms without acentral controller.Supporting consensus betweenfirms at the level of individual deals, not a global system.Supporting the inclusion of regulatory andsupervisory observer nodes.Validating transactions solely between parties tothe transaction.Supporting a variety of consensus mechanisms.Recording explicit links between human-languagelegal prose documents and smart contract code.Using industry-standard tools.Restricting access to the data within an agreementto only those explicitly entitled or logically privileged to it.

These features contribute to the design of a platform appropriatefor use in complex, financial services organizations. Note that this designdoes not use a native cryptocurrency or impose a global transaction speedlimit.

Corda尤其适用于受监管的金融机构。它很大程度上是受到区块链系统的启发,但又摒弃了很多不适合金融场景的传统区块链设计选择。

Corda提供了一个运行智能合约的框架，包括以下关键动作和特点：

通过基于现有合法框架和与现有新兴法案兼容的方式，纪录和管理两个及以上可识别的组织的金融协议和其他共享数据的变革；去中心化控制的公司间工作流设计；在个人交易层面上，支持公司间的共识机制，而不是全局系统；支持纳入监管以及监管观察员节点；仅仅在交易的参与方之间验证交易的有效性；支持各种各样的共识机制；纪录人类法律文件和智能合约代码之间的显性关联；使用符合行业标准的工具；严格准入合约数据，仅对有明确授权或逻辑上特权的用户开放。

Corda平台设计中的这些特性，适合复杂的金融服务机构。请注意，这项设计没有使用原生加密数字货币，也未设置全局性的交易限速。

4.2概念

We begin withthe idea of a global ledger: a reliable single source. However, in our model,it is not the case that transactions and ledger entries are globally visible.In cases where transactions only involve a small subgroup of parties we striveto keep the relevant data purely within that subgroup.

我们借鉴了全局性账本的概念：可靠的单一数据源。然而，在我们的模型里，交易和账本入口并未让全局可见。当交易仅发生在组织内一小部分群体间，我们努力仅在该群体内部保存相关数据。

The foundationalobject in our concept is astate object,which is a digital document which records the existence, content and currentstate of an agreement between two or more parties. It is intended to be sharedonly with those who have a legitimate reason to see it. To ensure consistencyin a global, sharedsystem where not all data is visible to all participants, we rely heavily onsecure cryptographic hashes to identify parties and data. The ledger is definedas a set of immutable state objects.

在我们的观念里，基础对象就是一个状态对象，是一个记录两个或多个组织间协议是否存在、以及协议内容和当前协议状态的数字化文档。该文档仅与有合法理由查看的用户共享。在一个各参与方无法可见全部数据的全球化共享系统中，要保持数据的一致性，我们严重依赖安全的加密哈希算法来辨认组织和数据。这个账本，则被定义为一个不可改变状态的对象集。

We talk andthink in terms of the state of agreements and our objective is to ensure thatall parties to the agreement remain in consensus as to this state as itevolves. One could argue that this is the essence of the blockchain concept:ensuring that the data held by different actors is, and remains, consistent as operationsare applied to update that data, and that this forms the foundation on whichreliable transactions are built: from simple monetary payments to sophisticatedsmart contract transitions.

我们依据协议状态以及我们的目标来讨论和思考，是为了确保在协议状态变化过程中，所有协议的签订方能够保持共识。有人可能认为这是区块链概念的本质：确保被不同角色持有的数据，在数据变化中保持并持续保持数据的一致性，才是保证可靠交易完成的基础：从简单的货币支付到复杂的智能合约交易。

图2

Figure 2: In the diagram above, we see a State object representinga cash claim of £100 against a commercial bank, ownedby a fictional shipping company.The state object explicitly refers by hash to its governing legal prose and tothe contract code that governs its transitions.

Our focus on states of agreements is in contrast to systems where the data overwhich participants much reach consensus is the state of an entire ledger or thestate of an entire virtual machine. Corda provides three main tools to achieveglobal distributed consensus:

Smart contract logic to ensurestate transitions are valid according to the pre-agreed rules.Uniqueness and timestampingservices to order transactions temporally and eliminate conflicts.An orchestration frameworkwhich simplifies the process of writing complex multi-step protocols betweenmultiple different parties.

图2所示，我们将一个状态对象看成某个虚拟的航运公司拥有在商业银行的£100现金协议。状态对象通过哈稀算法纪录其对应的法律文件和合约代码之间的显性关联关系，同时通过合约代码控制其转换。

我们专注于系统的协议状态，在系统数据层级上各参与者就整个分类账本或一个完整的虚拟机的状态达成共识。Corda提供了三个主要的工具来实现完全分布式的一致性目标：

智能合约，根据依靠预先约定的规则，确保状态转化的合法性。唯一的时间戳服务，以消除冲突同时保证事务顺序性。一个业务流程编排框架，来简化多个不同参与方之间繁杂协议流程的编写。

4.3共识机制

In Corda,updates are applied usingtransactions,which consume existing state objects and produce new state objects. There aretwo aspects of consensus:

1. Transactionvalidity: parties can reach certainty that a proposed update transactiondefining output states is valid by checking that the associated contract coderuns successfully and has all the required signatures; and that anytransactions to which this transaction refers are also valid.
2. Transaction uniqueness: parties can reach certainty that the transaction in questionis the unique of all its input states. That is: there exists no othertransaction, over which we have previously reached consensus (validity anduniqueness), that consumes any of the same states.

Parties canagree on transaction validity by independently running the same contract codeand validation logic. However, consensus over uniqueness requires apredetermined observer, which in many cases will be required to be independent.

在Corda中，使用“交易”来完成升级，在交易中使用已有的状态对象来生成新的状态对象。这是共识机制的两个方面：

1.交易合法性：参与方通过检查相关合约代码成功运行并持有全部必需的数字签名，便可以确认预期升级的可定义输出状态的交易是合法的，并且任何与之相关的交易都是合法的；

2.交易唯一性：参与方如果确认备选交易是所有输入状态的唯一使用者，即可确认交易的唯一性。也就是说，没有其他交易可以推翻我们之前达成的共识（有效性和唯一性），使用同一状态。

参与方通过独立运行相同的合约代码并验证其逻辑性，便可同意交易的合法性。然而，建立在唯一性基础上的共识机制，需要一个预定的观察员，很多情况下该观察员是独立的。

图3

Figure3: Consensus over transaction validity is performed only by parties to thetransaction in question. Therefore, data is only shared with those parties whichare required to see it. Other platforms generally reach consensus at the ledgerlevel. Thus, any given actor in a Corda system sees only a subset of the overalldata managed by the system as a whole. We say a piece of data is “onledger” ifat least two actors on the system are in consensus as to its existence anddetails and we allow arbitrary combinations of actors to participate in the consensusprocess for any given piece of data. Data held by onlyone actor is “off-ledger”.

图3所示，只有正在被确认中的交易，其参与方才能达成建立在交易合法性基础上的共识机制。因此，仅对必需查看数据的参与方共享数据，其他平台一般在账本层面达成共识。所以， Corda系统中的任何角色，仅能看到整个系统管理的全部数据的子集。我们把一小段数据叫做“账本上的数据”，如果系统中至少有两个在存在性和细节方面达成共识的角色出现，我们允许角色的任意组合参与到所指定数据块的建立共识进程中。仅被唯一角色拥有的数据，被称作为“账本之外的数据”。

Corda has “pluggable” uniqueness services. This is to improveprivacy, scalability, legal-system compatibility 4 andalgorithmic agility. A single service may be composed of many mutuallyuntrusting nodes coordinating via a byzantine fault tolerant algorithm, orcould be very simple, like a single machine. In some cases, like when evolvinga state requires the signatures of all relevant parties, there may be no needfor a uniqueness service at all.

Corda具有可插拔的唯一性服务，旨在提高隐私性、扩展性、分账系统的兼容性4和算法的敏捷性。一个独立服务，可能由众多相互无关的节点组成，这些节点通过一种拜占庭容错算法组合在一起，或可能非常简单，就是一台单独的机器。在很多情况下，例如涉及到一个状态问题就需要全部相关的参与方签名，但这对一个独立服务来说可能并不需要。

It is important to note that these uniqueness services arerequired only to attest as to whether the states consumed by a giventransaction have previously been consumed; they are not required to attest asto the validity of the transaction itself, which is a matter for the parties tothe transaction. This means that the uniqueness services are not required to(and, in the general case, will not) see the full contents of any transactions,significantly improving privacy and scalability of the system compared withalternative distributed ledger and blockchain designs. This design decisionrepresents an important choice as to
the acceptable tradeoffs in shared ledger architectures and is exploredmore fullyin the forthcoming technical whitepaper.

需要重点指出的是，这些独立服务仅需要证明，其状态是否被之前使用过状态的交易所使用；它们不必自己证明交易的合法性，那是交易参与方的事儿。这意味着，唯一性服务必需要看到任何交易的全部内容，意义在于相比其他分布式账本和区块链设计，提高了系统的隐私性和扩展性。这项设计决策，是在共享账本框架中做出权衡的重要抉择，在接下来的技术白皮书中将会做更全面探索。

4.4商业逻辑

Corda enforcesbusiness logic through smart contract code, which is constructed as a purefunction that either accepts or rejects a transaction, and which can be composedfrom simpler, reusable functions. The functions interpret transactions astaking states as inputs and producing output states through the application of (smartcontract) commands, and accept the transaction if the proposed actions arevalid. Contracts define part of the business logic of the ledger, and they are mobile:nodes will download and run contracts inside a sandbox without any review insome deployments, although we envisage the use of signed code for Cordadeployments in the regulated sphere.

Corda通过智能合约代码执行商业逻辑，这些业务代码由一段纯函数构成，只用来接受或者拒绝一次交易，这些功能可能是由更简单和可复用的功能组成。这些功能将交易解释为，通过应用（智能合约）命令来输入状态并生成输出状态，并且如果预期动作是合法的则确认交易。合约定义了账本的商业逻辑部分，而且是移动的：各个节点将会下载并在沙箱内运行合约，在某些部署中并无代码检查，尽管我们设想使用代码签名来监控Corda的合法部署。

The virtualmachine we have selected for contract execution and validation is the JavaVirtual Machine 5, as it has a wealth of existinglibraries and a large skill base, and reusing an industry standard makes iteasier for banks to reuse their existing code inside contracts. However, weaugment it with a custom sandbox that is radically more restrictive than theordinary JVM sandbox, and it enforces not only security requirements but alsodeterministic execution. Like Ethereum, the choice of standardising a bytecodeset rather than a language enables users to innovate in contract languagedesign, or reuse well known languages, according to taste. It also makes iteasy to directly use contract code from internal applications, once thatcontract has been reviewed, which should simplify application developmentconsiderably.

我们选择使用Java虚拟机5来执行合约和有效性验证，由于Java虚拟机有许多已有的库和技术积累，并且具有可复用的工业标准，对合约的代码重用使银行应用变得非常简单。然而，我们用它声明一个通用的沙箱，但是它比一个普通的JVM沙箱更为严格，这不仅加强安全需求，也提升对确定性执行的要求。类似以太坊，选择标准化字节码集而不仅是一门语言，促使用户在合约语言设计方面进行创新，或者根据自身喜好复用已有编程语言。这也使得直接使用内部程序的合约代码变得简单，一旦合约代码通过评估，它将会极大的简化应用程序开发。

4.5核心金融概念

Corda’sarchitecture was heavily influenced by threearchitecturallysignificantuse-cases, deemed to berepresentative of common problems to which it is likely to be targeted. Theseuse-cases are: cash, a security instrument and a derivative contract. In allthree cases, we conceive of them as examples of financial agreements:

A cash balance (e.g., “The following bank and Iagree that they owe me $1 million”).A security under custody (e.g., “The followingcustody bank and I agree that I own 1000 shares of the following corporation”).A bilateral derivative agreement (e.g., “Banks Aand B agree that they are parties to the following Interest Rate Swap (IRS),which means they agree to exchange the following cashflows (netted) atpredetermined scheduled times with an agreed payoff formula”).

Corda的基础架构深受三个架构领域影响深远的用例影响，被视为具有代表性的共同问题，也可能是有所针对性的。这三个用例包括：现金，证券托管和衍生合约。在这三个用例中，我们设想他们为金融协议案例：

现金（例如：以下银行，我同意他们欠我一百万美元）证券托管（例如：以下托管银行，我同意我拥有这些公司的1000股）双边衍生协议（例如：银行A和B同意他们是IRS的参与者，这意味着他们按照预定的时间以一个商定的公式对以下流转进行兑换）

Taking one ofthese examples, Corda’s cash design explicitly models the business reality thatthere is no such thing as “money in a bank”, only a cash claim that an ownerhas with respect to a named institution. 7 Soour core Cash contract is extremely simple, but powerful: we record the legalidentity of the cash issuer, the currency, amount, owner (and other informationas to the nature of the claim, with an explicit link to thelegalprosegoverning the agreement, which is also expected to specifyresolution procedures in the event of dispute) and use that to build up allother cash-related concepts (payments, netting and so forth).

就这些例子中的一个而言，Corda的现金设计，明确地将商业现实建模为没有“储存在银行中的钱”的情况，只有现金能表明其拥有者和一家署名机构有关系7。所以我们的核心现金合约非常简单，但是非常强大：我们记录现金当事人的合法身份、货币种类、数量、拥有者（其他信息比如原生声明，明确指定管理协议的规则，同时明确指定冲突事件中的解决流程）的标记，并且用于建立其他所有与现金相关的概念（支付，结算和其他）。

图4

Figure 4: Inthe diagram above, we see one of the simplest Corda transactions: an issuancetransaction. We see the creation of a new Cash state, issued by a commercialbank to a fictional shipping company. The issuing transaction is signed by theissuing bank. From this simple model, significantly more complicatedtransactions, such as payments, delivery-versus-payment contracts and future-datedobligations can be constructed.

图4所示，我们看到了一个最简单的Corda交易，一个发行交易。我们发现生成一个新的现金状态，由一家商业银行给一家虚构的航运公司，发行银行在交易中署名。从这个简单模型中，可以构造更复杂的交易，例如支付，对冲（delivery-versus-payment）合约，期债。

4.6 Corda模型的总结

The coreconcepts in our model are:

•Stateobjects, representing an agreement between two or more parties, governedby machine-readableContract Code.This code references, and is intended to implement, portions of human-readableLegalProse.

•Transactions,which transition state objects through a lifecycle

•TransactionProtocolsorBusiness Flow, enablingparties to coordinate actions without a central controller.

我们模型的核心概念是：

状态对象，代表两个或者多个参与方的协议，由机器可读的合约代码掌控，这些代码的引用，并且旨在执行人们可读的法律条文部分。交易，通过生命周期转化状态对象。交易协议和商业流程，在无中心控制的情况下使参与方能够协调动作。

Determinism is maximised and the amount of shared state requiredminimized by selectively and decisively restricting the universe of allowableprogramming techniques.

有选择性地严格限制可用的编程技术，让决定权最大化，但是可共享的状态数量必须最小化。

Thecombination of state objects (data), Contract Code (allowable operations), TransactionProtocols (business logic choreography), any necessary APIs, wallet plugins,and UI components can be thought of a Shared Ledger application, or CordaDistributed Application (“CorDapp”). This is thecore set ofcomponents a contract developer on the platform should expect to build.

状态对象（数据）的组合、合约代码（允许性操作）、交易协议（商业逻辑编排）、任何必要的API、钱包插件、UI组件，都可以被认为是一个共享的账本应用程序，或Corda分布式应用程序（CorDapp）。这是一个核心的组件集，是平台上任何一个合约开发者都期待去创建的。

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