1. Double spending is reusing digital assets intentionally or advertently. True or False?

a. True

b. False

2. In blockchain, cryptography ensures authenticity of a transaction, and also helps prevent double-spend. Is the above statement True or False?

a. True

b. False

3. After a hard fork, the emerging two chains are incompatible. True or False?

a. True

b. False

4. Bitcoin protocol runs over?

a. TCP

b. UDP



5. Which transaction(s) is/are valid with the current blockchain?

a. No conflict with other transactions

b. No double spending

c. No infinite loops

d. All of the above

6. What is correct order of adding a new block to a blockchain?

i. Block Mining

ii. Block Propagation

iii. Block Flooding

iv. Transaction Flooding

a. iii, iv, i, ii

b. iv, iii, ii, i

c. ii, i, iii, iv

d. iv, i, iii, ii

7. What are Bitcoin Exchanges available in India?

a. Coinbase

b. CoinDCX

c. UNOCoin

c. CoinSwitch Kuber

8. The primary difference between the permission less and permissioned blockchain is ___________?

a. Access control for the participants in the blockchain network

b. Hash Algorithms

c. Confidentiality

d. Availability

9. What is an advantage of permission less blockchain?

a. It does not use disinterested third parties to secure blocks, as participants have a vested interest

b. It is more resilient against fraud, because it uses federated nodes to combat fraud

c. It is open to everyone in the world without permission and licensing requirements

d. Its networks are by for-profit companies and the working of network is guaranteed

10. Which is/are the example/s of the double-spending attack?

a. Anita has a total of 80 unspent coins from two different transactions with an equal amount of bitcoins each. She sends the entire amount each to Deepak and Tanmay from one of the transaction

b. Bibhu bought a car using ‘p’ bitcoins. On delivery bitcoins are transferred from his wallet to the shopper’s wallet. Simultaneously, he uses that bitcoins for another purchase

c. Anita and Bibhu each have 40 unspent bitcoins. Both of them transfer 20 bitcoins to each other

d. Bibhu has 40 unspent bitcoins. He sends the entire amount each to Deepak and Tanmay

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