Week 8 Answers
1) Which of the following is/are correct?
a. POW always ensures consensus finality
b. POW does not ensure consensus finality
c. PBFT protocol always ensures consensus finality
d. PBFT protocol does not ensure consensus finality
Answer: B,C
2) Which of the following is/are true regarding the CoSi protocol?
a. Witnesses are organized in a tree structure
b. Three rounds of PBFT can be emulated using one round of CoSi protocol
c. It can be used to sign a message by multiple authorities collectively
d. Three rounds of PBFT can be emulated using two rounds of CoSi protocol
Answer: A,C,D
3) Which of the following factor(s) distinguish Bitcoin-NG from Bitcoin?
a. Decoupling the leader election and transaction serialization
b. Use of key blocks and macroblocks
c. Bitcoin-NG has lower transaction throughput as compared to Bitcoin
d. Leader election using PBFT
Answer: A,B
4) Which of the following is/are true regarding Bitcoin-NG?
a. Microblock generation rate is lower than the key block generation rate
b. Microblock generation rate is higher than the key block generation rate
c. The interval between the generation of two key blocks is exponentially distributed
d. The key block contains the ledger entries
Answer: B,C
5) Which of the following is/are correct?
a. PBFT protocol ensures total ordering of transactions
b. Bitcoin has lower node scalability as compared to Standard BFT protocols
c. Standard BFT protocols never produce lower transaction throughput as compared to Bitcoin
d. Bitcoin-NG has higher node scalability as compared to Standard Bitcoin protocols in general
Answer: A,D
6) What is the primary function of a Fabric smart contract (Chaincode)?
a. Performing cryptocurrency mining
b. Defining the business rules and logic in the ledger
c. Defining consensus algorithms
d. Monitoring the transaction throughput
Answer: B
7) Which API is used for implementing Fabric chaincodes?
a. hyperledger-client-api
b. smart-contract-builder
c. fabric-contract-api
d. fabric-identity-manager
Answer: C
8) Which of the following is/are true regarding fabric transactions?
a. The transactions should be endorsed by peers
b. The transactions are committed without validation
c. A transaction does not change the world state
d. World state holds the current updated consensus view
Answer: A,D
9) Which of the following factor(s) limit Bitcoin’s scalability?
See alsoBlockchain and its Applications Assignment 3 Answers
a. Low transaction fees
b. Fixed block size
c. Wallet address complexity
d. Fixed block frequency
Answer: B,D
10) Which of the following is/are correct regarding Schnorr Multisignature in CoSi protocol?
a. It is difficult to verify the signature
b. Signature can be verified using a single collective public key
c. It is easy to verify the signature
d. It relies on group G of any composite order
Answer: B,C
