Test your knowledge: Corda

Are you CordaCon ready? Would you like to test your knowledge before the biggest Corda event of the year, or widen your understanding of one of the most popular enterprise blockchains? Then this is exactly what you are looking for!

1. If you wish to challenge yourself on your existing understanding of how Corda works, then dive right into the quiz with no peeking through the answers beforehand. Score yourself, come back to the rest of the blog to check on your answers and deepen your knowledge thanks to the additional resources that we have curated for you.
2. Are you instead looking for a great way to help you brush up on the understanding of Corda, and learn new things to build on your existing knowledge base? Then start by reading through the answers carefully, follow the additional resources we have included for each question, and take the quiz at the end to check how far you’ve gone in your learning session.

The best part? Take the quiz and pass with a score of 80% or above, and we will send you a certificate of completion that will show to the entire R3 ecosystem that you are indeed CordaCon ready.

Ready to take the quiz? Let’s go!

The Knowledge Team here at Chainstack is committed to contributing to the blockchain community with high quality resources and opportunity for training. We hope you will enjoy this piece, and join us for more—including bootcamps and online seminars. Happy learning!

When you are ready to view the quiz with the correct answers, the explanations and the additional resources, just expand the section below.

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1. How is information shared between nodes in Corda? 

It is up to you how to use this learning material, but we can suggest two ways:

[X] Peer-to-peer

[ ] Through the notary service

[ ] Through the network map service

Explanation: The correct answer is peer-to-peer. Nodes communicate and share information point-to-point. The notary service protects the network from double-spends and timestamps the transactions. The network map service is basically a catalogue of nodes on the network. Read more at Corda docs: Network.

2. Any new node can join a Corda network if the majority of the existing nodes on the network accept the new node.

[ ] True

[X] False

Explanation: A Corda network is permissioned. Each Corda network is run by a network operator. The network operator admits new nodes to the network. Read more at Corda docs: Admission to network.

3. How do nodes discover other nodes on a Corda network?

[ ] By using Kademlia-like table

[X] Through the network map

[ ] By establishing communication channels with each other

Explanation: The correct answer is the network map service. The network map service is basically a maintained catalogue of nodes on a Corda network. Read more at Corda docs: The network map. The Kademlia-like table is how Ethereum works; and communication channels is how Hyperledger Fabric works.

4. Each node on the Corda network keeps the exact same ledger copy.

[ ] True

[X] False

Explanation: Each node on a Corda network only keeps the data extracted from the ledger relevant to the node. Read more at Corda docs: Ledger.

5. CorDapps can be written in the following languages:

[ ] Java & JavaScript

[X] Java & Kotlin

[ ] JavaScript & Go

Explanation: Corda—mainly targeting enterprises and finance organizations—focuses on Java & Kotlin. Corda nodes are also JVM instances.

6. Communication between Corda nodes is encrypted.

[X] True

[ ] False

Explanation: All nodes communication on a Corda network is always TLS encrypted. Read more at Corda blog: Corda Enterprise Kubernetes Deployment.

7. A Corda node is an instance of a Java Virtual Machine.

[X] True

[ ] False

Explanation: Embedding the Java Virtual Machine specification was one of the crucial design decisions for Corda to attract developers and to use existing toolchains. Read more on JVM at Corda docs: Deterministic JVM.

8. What is a state in Corda?

[X] A fact known by one or more parties

[ ] A state of the network with all the transactions at a point in time

[ ] The state of finality of the ledger

Explanation: A state is an on-ledger fact relevant to the node that stores the state in its vault. Read more at Corda docs: States.

9. What is a vault in Corda?

[X] A table of values extracted from the ledger and relevant to the node

[ ] A secure key storage

[ ] A storage for file attachments (e.g. PDF invoices)

Explanation: A vault is the data that is relevant to the node, extracted from the ledger, and stored as a table that can be queried. Read more at Corda docs: Vault.

10. Once deployed, a contract on a Corda network is accessible by all network participants.

[ ] True

[X] False

Explanation: Unlike on public blockchain networks (e.g. Ethereum), a contract on Corda must be hosted only on selected nodes that have to interact with each other within this specific contract rules and confines. Read more at Corda docs: Contracts.

11. Once deployed, contracts are upgradeable on a Corda network.

[X] True

[ ] False

Explanation: It’s pretty much a prerequisite for any enterprise blockchain platform or protocol to have upgradeable contracts. Read more at Corda docs: Upgrading contracts.

12. An oracle on a Corda network must see the entire contents of a transaction to sign it.

[ ] True

[X] False

Explanation: Confidentiality is a must for an enterprise blockchain platform or protocol. Oracles on a Corda network only need to see the contents that relate to the oracle service, not the full transaction details. Read more at Corda docs: Transaction tear-offs.

13. A Corda network can have several notary clusters with different consensus algorithms.

[X] True

[ ] False

Explanation: Any Corda network can have different notary clusters set up, each of the clusters can have a different consensus algorithm. Read more at Cord docs: Notaries.

14. A typical CorDapp consists of the following components:

[X] Contract, State, Flow

[ ] Contract, Ledger, Flow

[ ] Contract, Transaction schema, Party definition

Explanation: Think of a CorDapp as an app that has enforceable rules (contract), objects to work with (state), and a logic to follow (flow). Read more at Corda docs: What is a CorDapp?

15. The number of nodes that can be a part of a transaction is limited for performance reasons to:

[ ] 10

[ ] 100

[X] Not limited

Explanation: Corda is scalable. There is no limit to how many nodes should be a part of a transaction. On top of that, there’s additional scalability possibilities that’s good to be familiar with in the form of Corda Accounts. Read more at Corda blog: Unlocking New Opportunities with Accounts on Corda.

16. A transaction on a Corda network can be broadcast to all network participants.

[ ] True

[X] False

Explanation: Node communication on a Corda network is always point-to-point and encrypted. Read more at Corda docs: Point-to-point vs. global broadcasts.

17. If a transaction between nodes must include a PDF invoice, the PDF will:

[ ] Be sent as an attachment in the transaction

[X] Be uploaded to a node and referenced in the transaction by the hash of the PDF file

[ ] Be included in the network map service as a catalogued object and referenced by the transaction

Explanation: Transactions only use the hash of an attachment that is uploaded on a node and can be downloaded from the node. Read more at Corda docs: Using attachments.

18. What does an oracle service do on a Corda network?

[X] Provide data external to the network into a transaction and signs the transaction

[ ] Establish multiple datapoints for the network that the nodes votes on

[ ] Provide external cross-chain services

Explanation: Oracles provide external data and put their signature on the transaction using the external data they provided. Oracles provide determinism to the network. Read more at Corda docs: Oracles.

19. A notary on a Corda network has to authorize every single transaction.

[ ] True

[X] False

Explanation: A notary protects the network from double-spends and timestamps the transactions. When there is no input state for a transaction or a time-window in which the transaction has to be executed, there is no requirement for a notary to notarize a transaction. Read more at Corda docs: Notaries.

20. Transaction validation always includes walking back the entire chain and verifying it by the participating nodes.

[ ] True

[X] False

Explanation: Notaries validate transactions based on the consumed and unconsumed states. Read more at Corda docs: Validation.

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