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47 lines
3.2 KiB
ReStructuredText
47 lines
3.2 KiB
ReStructuredText
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Corda ecosystem
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===============
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A Corda network consists of the following components:
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* Nodes, where each node represents a JVM run-time environment hosting Corda services and executing applications ("CorDapps").
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Nodes communicate using AMQP/1.0 over TLS.
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* A permissioning service that automates the process of provisioning TLS certificates.
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* A network map service that publishes information about nodes on the network.
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* One or more pluggable notary service types (which may be distributed over multiple nodes).
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A notary guarantees uniqueness and validity of transactions.
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* Zero or more oracle services. An oracle is a well known service that signs transactions if they state a fact and that fact is considered to be true.
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* CorDapps which represent participant applications that execute contract code and communicate using the flow framework to achieve consensus over some business activity
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* Standalone Corda applications that provide manageability and tooling support to a Corda network.
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These components are illustrated in the following diagram:
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.. image:: resources/cordaNetwork.png
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:align: center
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Note:
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* Corda infrastructure services are those which all participants depend upon, such as the network map and notaries.
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* Corda services can be deployed by participants, third parties or a central network operator (eg. such as R3);
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this diagram is not intended to imply only a centralised model is supported
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It is important to highlight the following:
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* Corda is designed for semi-private networks in which admission requires obtaining an identity signed by a root authority.
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* Nodes are arranged in an authenticated peer to peer network. All communication is direct.
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* Data is shared on a need-to-know basis. Nodes provide the dependency graph of a transaction they are sending to another node on demand, but there is no global broadcast of all transactions.
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* Nodes are backed by a relational database and data placed in the ledger can be queried using SQL
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* The network map publishes the IP addresses through which every node on the network can be reached, along with the identity certificates of those nodes and the services they provide.
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* All communication takes the form of small multi-party sub-protocols called flows.
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* Oracles represent gateways to proprietary (or other) business logic executors (e.g., central counterparties or valuation agents) that can be verified on-ledger by participants.
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CorDapps
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--------
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Corda is a platform for the writing of “CorDapps”: applications that extend the distributed ledger with new capabilities.
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Such apps define new data types, new inter-node protocol flows and the “smart contracts” that determine allowed changes.
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The combination of state objects (data), contract code (allowable operations), transaction flows (business logic
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choreography), any necessary APIs, vault plugins, and UI components can be thought of as a shared ledger application,
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or corda distributed application (“CorDapp”). This is the core set of components a contract developer on the platform
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should expect to build.
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Examples of CorDapps include asset trading (see :ref:`irs-demo` and :ref:`trader-demo`), portfolio valuations (see :ref:`simm-demo`), trade finance,
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post-trade order matching, KYC/AML, etc.
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