R3 Corda Key Concepts: The Corda distributed ledger

Now that we have a conceptual understanding of what the Corda platform is - it’s time to learn about the components and key concepts that make it work. Before we check about the Ledger first we will check about the Network then we will move towards the ledger.

What is a network?

A Corda network is made up of nodes, which represent real-world legal identities. Each node runs an instance of Corda and one or more CorDapps. Nodes communicate point-to-point not by global broadcast. Each node has a certificate that maps its network identity to a real-world legal identity. Corda networks are semi-private you need a certificate from the network operator to join. People and businesses using Corda can communicate over a peer-to-peer network.

On Corda, people and businesses interact by communicating over a peer-to-peer network of Corda nodes. Each node represents a legal entity running Corda and one or more Corda-distributed applications, known as CorDapps.

Corda is different from other distributed ledgers because all communication between nodes is point-to-point, and only shared on a need-to-know basis. It’s also encrypted using transport-layer security. There are no global broadcasts to all parties on a network, but all of the nodes in a network can send messages directly to other nodes. If the recipient is offline, the message waits in an outbound queue until they are online again just like an email.

To Join a network

Unlike traditional blockchain, Corda networks are semi-private. To join a network, you must obtain a certificate from the network operator. This certificate maps the node’s identity on Corda to a real-world legal identity and a public key.

The network operator enforces rules that stipulate what information nodes must provide and the know-your-customer (KYC) processes they must undergo before being granted this certificate.

Node identities

The network map service matches each node's identity to an IP address. Nodes use these IP addresses to send messages to each other.

Nodes can also generate confidential identities for individual transactions. The certificate chain linking a confidential identity to a node identity or real-world legal identity is only distributed on a need-to-know basis. Nodes can use confidential identities to protect themselves in the event that an attacker gets access to an unencrypted transaction. The attackers cannot identify the participants without additional information.

Find other nodes on a network

Corda nodes discover each other via a network map service. You can think of this service as a phone book, which publishes a list of peer nodes that includes metadata about who they are and what services they can offer.

Now let's check about the Ledger.

The Corda Ledger

A distributed ledger is a database of facts that are replicated, shared, and synchronized across multiple participants on a network. Participants are referred to as nodes and their copy of the ledger is held in their vault. Each node has a different view of the ledger, depending on the facts it shares. Nodes that share a fact must reach a consensus before it’s committed to the ledger. Two nodes always see the exact same version of any on-ledger facts they share.

Ledger is a subjective construct from each peer’s point of view there are no peers that see everything.

Visibility of data on the ledger

Corda does not have a central store of data. Each node maintains its own database of facts–things it knows to be true based on its interactions. Facts are known by different nodes/peers which may be off-ledger or on-ledger. The intersection of two nodes/peers represents on the ledger shared facts that are known by those two peers. The whole ledger is everything that is shared. For example, if there are nodes representing Alice and Bob on the network and Alice loans Bob some money, both Alice and Bob will store an identical record of the facts about that loan. If the only parties involved with the loan are Alice and Bob, then they are the only nodes that ever see or store this data.

This diagram shows a network with five nodes (Alice, Bob, Carl, Demi, and Ed). Each numbered circle on an intersection represents a fact shared between two or more nodes:

ALICE = { 1, 7 }

BOB = { 1, 7, 6, 5 }

CARL = { 9, 4, 6, 5, 2, 3}

DEMI = { 2, 3, 8 }

ED = { 9, 4, 8, 3 }

In the diagram, facts 1 and 7 are known by both Alice and Bob. Alice only shares facts with Bob, Alice doesn’t share any facts with Carl, Demi, or Ed.

Each node only sees a subset of facts their own facts and those that they share with others. No single node can view the ledger in its entirety. For example, in the diagram, Alice and Demi don’t share any facts, so they see a completely different set of facts from each other.

Shared facts

On Corda, no central ledger records facts for all of the nodes on a network. Instead, each node maintains its own vault, which contains all of its known facts. Each network peer maintains a separate vault of facts. Facts can be thought of as a row in a table. All peers to a shared facts stored identical copies. Not all on-ledger facts have to be shared with other peers.

You can think of a vault as being a database or a simple table. In this diagram, facts 1 and 7 appear on both Alice’s vault and Bob’s vault and are therefore shared facts:

When multiple nodes on a network share an evolving fact, the changes to the fact update at the same time in each node’s vault. This means that Alice and Bob will both see an identical version of shared facts 1 and 7.

On-ledger facts don’t have to be shared between nodes. For example, fact 11 in Alice’s vault is not shared with Bob. Facts that are not shared are unilateral facts.

Although there is no central ledger, you can broadcast a basic fact to all nodes of a network using the network map service.

Conclusion

In conclusion, the R3 Corda platform is constructed on pillars of key concepts, distributed ledger, and network architecture. Point-to-point messaging and encryption facilitate peer-to-peer communication through nodes in the Corda network that node represent real-world legal identities. Unlike traditional blockchain platforms, however, Corda networks are semi-private and require parties to have certificates from network operators. It is a network map service that manages node identities by ensuring secure and authenticated interactions between participants. Each node keeps its own set of facts in the Corda ledger allowing for subjective views of the ledger based on shared interactions. The consensus process by which participant nodes must agree before shared facts are committed to the ledgers ensures synchronization and integrity.

In addition, the Corda ledger has restricted access whereby every node owns some specific facts due to the interaction done. As such, this sort of decentralized approach toward managing ledgers ensures privacy and confidentiality since any node has only those factual databases where it is involved directly or shared with others. These shared facts are all modified simultaneously so that consistency and openness can be maintained throughout the network. Although there is no centralized ledger, Corda allows the sharing of common facts with all nodes through a network map service. This has facilitated wide communication when needed. In summary, the Corda distributed ledger together with its network architecture facilitates secure and efficient interaction among participants by focusing on privacy thus making it a fascinating platform for various applications across industries.

Reference:

https://r3.com/

https://corda.net/