About this previous year paper
SECTION A (2 × 10 = 20 Marks)
Attempt all questions in brief
a) Define cryptographic hashing.
Cryptographic hashing is a process that converts input data of any size into a fixed-length string using a hash function, ensuring data integrity, immutability, and security. Even a small input change produces a completely different hash.
b) Differentiate between hashchains and blockchains.
Hashchain: A sequence of hashes where each hash depends on the previous one. Used mainly for data integrity.
Blockchain: A distributed ledger where blocks contain transactions, linked via hashes, validated by consensus mechanisms.
c) Design goals of consensus protocols in permissioned blockchains.
Fault tolerance High throughput
Low latency Security against malicious nodes
Deterministic finality
d) Permissioned vs permissionless consensus mechanisms.
Permissioned: Known validators, uses PBFT, Raft → fast & efficient
Permissionless: Open participation, uses PoW/PoS → slower but decentralized
e) Steps in designing and implementing chaincode in Hyperledger Fabric.
Define business logic Write chaincode (Go/Java/Node.js)
Package and install Define endorsement policy
Deploy on channel Invoke and test transactions
f) Role of endorsement policy in transaction validity.
It specifies which peers must approve a transaction. A transaction is valid only if endorsements match the policy before ordering and committing.
g) Use of blockchain in insurance industry. Fraud reduction
Smart contracts for claims Transparent policy management
Faster claim settlement
h) Blockchain in KYC efficiency and security.
Blockchain enables single-time verification, immutable identity records, secure data sharing, and reduces duplication and fraud.
i) Benefits for intergovernmental record-keeping.
Transparency Tamper-proof records
Faster verification Reduced corruption
Improved trust between agencies
j) Security vulnerabilities in blockchain-based digital identity systems.
Private key loss Smart contract bugs
Sybil attacks Poor off-chain data security
Centralized identity issuers
SECTION B (10 × 3 = 30 Marks)
Attempt any three
a) Distributed ledger vs centralized database
Centralized databases rely on a single authority, making them vulnerable to failure and manipulation. Distributed ledgers replicate data across nodes, ensuring integrity, transparency, and availability.
Example: Banking server vs blockchain ledger.
b) Proof of Elapsed Time (PoET) vs PoW
PoET uses trusted execution environments to randomly assign wait times, consuming low energy.
PoW requires heavy computation, high energy, and slower finality.
c) Consensus decomposition in Hyperledger Fabric
Fabric separates: Transaction execution
Ordering Validation
This modular design improves scalability, flexibility, and performance.
d) Blockchain in financial settlements
It enables real-time settlement, removes intermediaries, reduces counterparty risk, and automates reconciliation using smart contracts.
e) Quantum computing impact on blockchain cryptography
Quantum computers can break RSA and ECC. Governments need quantum-resistant algorithms like lattice-based cryptography to secure future blockchains.
SECTION C (10 × 5 = 50 Marks)
Attempt one from each question
Q3(a) Public vs Private Blockchains
| Aspect | Public | Private |
|---|---|---|
| Access | Open | Restricted |
| Consensus | PoW/PoS | PBFT/Raft |
| Speed | Slow | Fast |
| Use cases | Crypto | Enterprise |
Q4(a) Scalability limitations & solutions
Limitations: Low TPS
High latency Network congestion
Solutions: Sharding
Layer-2 solutions Sidechains
Improved consensus algorithms
Q5(a) Security features of Hyperledger Fabric
Permissioned access Channel-based privacy
Endorsement policies MSP-based identity management
Immutable ledger ensures integrity
Q6(b) Traditional vs blockchain supply chain
Blockchain benefits: Transparency
Traceability Fraud reduction
Limitations: Integration cost
Scalability issues Regulatory uncertainty
Q7(b) Blockchain-based digital identity systems
Blockchain provides tamper-proof, user-controlled identities, eliminates duplication, improves trust, and is superior to centralized identity systems vulnerable to breaches.