Blockchain Scalability and its Foundations in Distributed Systems | Week 1

2 months ago
Posted by PROGIEZ
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Course Name: Blockchain Scalability and its Foundations in Distributed Systems

Course Link: Blockchain Scalability and its Foundations in Distributed Systems

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Module 1 quiz

Q1. Which of the following milestones marked the beginning of the history of blockchain?

  • Blind signature was proposed as a form of electronic carbon copy for payment systems.
  • Bitcoin protocol was written.
  • Cryptography was made available to the public via the Data Encryption standard.
  • The cypherpunk mailing list was created.

Answer: Cryptography was made available to the public via the Data Encryption standard.

Q2. The cypherpunk mailing list was created:

  • before the release of the Bitcoin paper.
  • after the release of the Bitcoin paper.

Answer: before the release of the Bitcoin paper.

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q3. In 1998, Wei Dai sent a message on the cypherpunk mailing list, describing a system called “b-money”. The system Dai described included a significant idea that is being used in blockchain systems today.
What was the significant idea first proposed in the “b-money” system?

  • Application of a chain of hash to guarantee immutability
  • Public keys to represent user accounts
  • A protocol to transfer cryptocurrency in a peer-to-peer fashion without the need of any intermediary

Answer: Public keys to represent user accounts

Q4. Ethereum, the system first proposed by Vitalik Buterin, was commonly hailed as “Blockchain version 2.0”. Although this system was based on crypto-puzzles, it was said to extend the notion of cryptocurrency.
Ethereum extended the concept of cryptocurrency by allowing users to:

  • upload transactions.
  • upload smart contracts.
  • transfer cryptocurrency in a peer-to-peer fashion.

Answer: upload smart contracts.

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q5. What prevents a participant from withdrawing coins from someone else’s account in a blockchain?

  • Participants have to pass a clearance check before they can start issuing transactions.
  • A key, which is private to the owner of the account, must be used in order to sign the transaction.

Answer: A key, which is private to the owner of the account, must be used in order to sign the transaction.

Q6. A blockchain is an abstraction that can be viewed as a DAG.
What does DAG stand for?

  • Directly Assisted Graph
  • Directed Acyclic Graph
  • Directed Asymmetric Graph

Answer: Directed Acyclic Graph

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q7. True or False?
The pointer is a representation of a hash of the source block that the destination block contains.

  • True
  • False

Answer: False

Q8. Consider this sentence: “the pair is a pointer of P”.
What is the role of b1 in this relationship?

  • Destination block
  • Source block

Answer: Source block

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q9. Participants or issuers in a blockchain have two keys: a private key and a public key.
Which of these keys can be used by a server to identify whether a transaction was correctly signed by an issuer who would like to propagate a transaction to the network?

  • Private key
  • Public key

Answer: Public key

Q10. Which of the following is correct regarding the genesis block?

  • It defines the start of the blockchain.
  • It is known only to the miners who create the new block to be appended to the blockchain.
  • It points to other blocks in the blockchain.

Answer: It defines the start of the blockchain.

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q11. What does it mean when a blockchain abstraction is implemented in a distributed way?

  • For multiple processes, the view they have of the same blockchain is always the same.
  • For multiple processes, the view they have of the same blockchain can be different.

Answer: For multiple processes, the view they have of the same blockchain can be different.

Q12. What can go wrong during the blockchain execution given its distributed nature?

  • Two nodes may not have the same genesis block.
  • Two nodes may disagree on a block at a given index higher than the genesis block.

Answer: Two nodes may disagree on a block at a given index higher than the genesis block.

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q13. True or False?
There would be a disagreement if the blockchain was guaranteed to remain a chain, linking a single block after another, instead of a DAG.

  • True
  • False

Answer: False

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q14. What would be the advantages and disadvantages of having a single copy of the blockchain that all processes would need to access?

  • The access time would be reduced but there could still be disagreement.
  • There would not be any disagreement but the transactions one could include in the blockchain would be conflicting.
  • The blockchain would be easier to access but there could still be disagreement.
  • There would not be any disagreement, but the system would not tolerate failures.

Answer: There would not be any disagreement, but the system would not tolerate failures.

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

Q15. After some time, one could expect that Bob and Carole exchange their views so that they can detect disagreement. What could prevent them from detecting this disagreement?

  • Not knowing which blocks to compare
  • A network delay
  • A conflicting transaction

Answer: A network delay

These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz

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These are Blockchain Scalability and its Foundations in Distributed Systems Week 1 Answer Coursera Quiz
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