IT-803-A Blockchain Technology - May 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aDifferentiate between public and private blockchain.
   How to answer

   • Define public blockchain with open permissionless participation and private blockchain with restricted permissioned participation
   • Compare on access, consensus, decentralization, security, speed and use-cases
   • Give examples e.g. Bitcoin/Ethereum vs Hyperledger Fabric/Corda
   • Conclude suitability for different applications
2. 7 Marks
   bWhat is Cryptographic Hash Function? Write the Properties of a hash function.
   How to answer

   • Define cryptographic hash function as deterministic one-way mapping to fixed-size digest
   • List properties: pre-image resistance, second pre-image resistance, collision resistance, avalanche effect, determinism, fast computation
   • Explain role in blockchain linking and integrity
   • Give examples e.g. SHA-256
3. 7 Marks
   aWhat is the Merkle tree? Explain the usage of Merkle tree.
   How to answer

   • Define Merkle tree as binary hash tree with transactions as leaves and Merkle root on top
   • Explain construction by pairwise hashing up to root
   • Explain uses: efficient verification, SPV, data integrity, tamper detection
   • Mention use in Bitcoin block header
4. 7 Marks
   bWhat is the Monopoly Problem? Explain in detail about Attacks on Proof of Work.
   How to answer

   • Define monopoly problem as single miner/pool controlling majority hash power
   • Explain 51% attack, selfish mining, double spending, denial of service
   • Explain attacks on Proof of Work in detail
   • Discuss mitigations and decentralization need
5. 7 Marks
   aWhat is Bitcoin P2P Network and how transactions are processed in Bitcoin Network?
   How to answer

   • Define Bitcoin P2P network as decentralized peer-to-peer overlay without central server
   • Outline transaction lifecycle: creation, signing, broadcast, validation, mempool, mining, confirmation
   • Explain role of nodes, miners and flooding protocol
   • Mention verification of signatures and UTXO
6. 7 Marks
   bWhat is the double spending problem and how it is prevented in the Block chain?
   How to answer

   • Define double spending as spending same digital coin twice
   • Explain why possible in digital cash without central authority
   • Explain prevention via UTXO, confirmation, Proof of Work and longest chain rule
   • Mention 51% risk and confirmations
7. 7 Marks
   aWhat is a Permissioned block chain? Explain the design issues of Permissioned block chains.
   How to answer

   • Define permissioned blockchain with authenticated known participants
   • Explain design issues: identity management, access control, consensus choice, scalability, privacy
   • Discuss governance and membership services
   • Give examples e.g. Hyperledger Fabric
8. 7 Marks
   bExplain the Lamport-Shostak-Pease BFT Algorithm.
   How to answer

   • State Byzantine Generals problem and need for BFT
   • Outline Lamport-Shostak-Pease oral message algorithm steps and rounds
   • Explain 3m+1 requirement to tolerate m traitors
   • Mention limitations and relevance to blockchain
9. 7 Marks
   aDefine Consensus. Explain in detail about the Distributed consensus in the closed environment.
   How to answer

   • Define consensus as agreement among distributed nodes on single state
   • Explain distributed consensus in closed/permissioned environment with known identities
   • Discuss algorithms e.g. PBFT, RAFT, Paxos and phases
   • Mention fault tolerance and finality
10. 7 Marks
    bExplain in detail Block chain enabled trade.
    How to answer

    • Define blockchain-enabled trade as use of distributed ledger for trade finance
    • Explain smart contracts, provenance, settlement and disintermediation
    • Discuss benefits: transparency, speed, reduced fraud
    • Give trade use-case examples
11. 7 Marks
    aExplain the Cross border payments Enterprise application of block chain.
    How to answer

    • Define cross-border payments problem: slow, costly correspondent banking
    • Explain blockchain enterprise solution with shared ledger, real-time settlement
    • Discuss Ripple/Stellar type models, compliance and FX
    • List benefits and challenges
12. 7 Marks
    bExplain how it is possible to Mortgage over the Block chain?
    How to answer

    • Explain mortgage as tokenized property and loan agreement on ledger
    • Describe smart contract for escrow, repayments, title transfer
    • Explain identity, provenance and fraud prevention
    • Discuss benefits and legal challenges
13. 7 Marks
    aDefine Hyper ledger. Explain the Hyper ledger Fabric Architecture.
    How to answer

    • Define Hyperledger as open-source enterprise blockchain project under Linux Foundation
    • Explain Fabric architecture: peers, orderers, MSP, channels, chaincode, endorsement policy
    • Describe execute-order-validate flow
    • Mention privacy and modularity benefits
14. 7 Marks
    bDefine Smart contract. Explain the process of writing smart contracts using Ethereum.
    How to answer

    • Define smart contract as self-executing code on blockchain
    • Outline steps in Ethereum: Solidity, Remix, compilation, deployment, gas, invocation
    • Explain EVM and ABI role
    • Give simple example flow
15. 14 Marks
    Write short notes on any two of the following:

    1. a)Public Key Cryptography
    2. b)HashCash PoW and Bitcoin PoW
    3. c)RAFT Consensus
    4. d)Identities and Policies of Hyper ledger Fabric
    How to answer

    • For each chosen topic give definition and key principles
    • Explain working with diagram/steps where relevant
    • Mention blockchain relevance and example
    • Conclude with advantages/limitations