These are Blockchain and its Applications Assignment 1 Answers
Q1. What are the features of a hash function? a. Puzzle-friendly b. Collision-resistance c. Deterministic d. Post image resistance
Answer: a. Puzzle-friendly b. Collision-resistance c. Deterministic
Q2. For a SHA 256 bit hash function, the attacker needs to compute how many hash operations in order to find two matching outputs? a. 0.3 x2^128 b. 0.2×10^50 c. 0.25X2130 d. 1 x2256
Answer: c. 0.25X2130
Q3. What is the hash value of 6666 if SHA-256 is used? a. b. c. d.
These are Blockchain and its Applications Assignment 1 Answers
Q4. Which of the statements below is/are true for decentralized distributed systems? a. Players may or may not trust each other b. Players must trust each other c. Central body should govern the communication d. None of the above
Answer: a. Players may or may not trust each other
Q5. Miner nodes only execute new transactions but can not verify previous transaction hash? a. True b. False
Answer: b. False
Q6. Which of the following is/are true for blockchains? a. Works based on Push technique b. Existing data can be deleted easily c. Tamper-proof d. None of the above
Q7. Where are the ledger logs stored in a blockchain? a. On a SQL Database b. On a central immutable ledger c. On a metadata table d. In ledger of each peer
Answer: d. In ledger of each peer
Q8. Which of the following is an avalanche effect to a cryptographic hash function? a. given the same message the hash function would not return the same hash b. it is not very difficult to generate the original message from the hash c. a small change in the message, impacts large change the hash value d. None of the above
Answer: c. a small change in the message, impacts large change the hash value
Q9. Genesis blocks may not contain the a. First transaction b. First transaction block c. Last transaction block d. None of the above
Answer: c. Last transaction block
These are Blockchain and its Applications Assignment 1 Answers
Q10. Which of the below is/are blockchain based app examples? a. Cross-border payments b. Supply chain c. Anti-money laundering tracking system d. UTXO
Answer: a. Cross-border payments b. Supply chain c. Anti-money laundering tracking system
These are Blockchain and its Applications Assignment 1 Answers
Q1) Which one is true for an ideal decentralized solution for business management? a. A centralized authority should decide the overall trust b. Everyone should trust and cooperate with each other c. No one should trust and cooperate with each other d. No one should trust each other, however they should cooperate
Answer: d. No one should trust each other, however they should cooperate
Q2) Which of the statements below is/are true for successful run of decentralized distributed systems? a. Network of different players b. Players must trust each other c. If they cooperate, the society gets benefitted d. None of the above
Answer: a, c
Q3) Where are the transactions logs recorded in a blockchain? a. Centralized editable database b. Editable log file c. On centralized immutable database d. On append only distributed immutable ledger
Answer: d. On append only distributed immutable ledger
These are Blockchain and its Applications Assignment 1 Answers
Q4) What are the properties of cryptographic hash function? a. It should be deterministic b. It should be collision free c. Ability to hide the input message d. Puzzle friendly
Answer: a, b, c, d
Q5) For a 512 bit hash function, the attacker needs to compute how many hash operations in order to find two matching outputs in the initial round? a. 2512 b. 2128 c. 2256 d. 260
Answer: c. 2256
Q6) Which of the following is a correct statement about a cryptographic hash function? a. given the same message the hash function would not return the same hash b. it is not very difficult to generate the original message from the hash c. a small change in the message, impacts the hash value d. one can easily find two different messages with same hash
Answer: c. a small change in the message, impacts the hash value
These are Blockchain and its Applications Assignment 1 Answers
Q7) What are the security features of a hash function? a. Non-deterministic b. Puzzle-friendly c. Collision-resistance d. Preimage resistance
