BLOCKCHAIN ARCHITECTURE DESIGN (KCS-714)
B.Tech SEM VII – Complete Solved Question Paper (2022–23)
⏱ Time: 3 Hours | 📊 Marks: 100
SECTION A
Attempt all questions in brief (2 × 10 = 20 marks)
(a) How does Blockchain differ from relational databases?
Blockchain is a decentralized, distributed ledger where data is immutable and stored in blocks linked cryptographically, whereas relational databases are centralized, allow data modification, and rely on a single authority for control
(b) Types of records present in blockchain database
Blockchain contains transaction records, block headers, hash pointers, timestamps, and smart contract data, all stored in an append-only structure
(c) Why is consensus mechanism required in blockchain?
Consensus mechanisms ensure that all participating nodes agree on the same version of the ledger, preventing fraud, double spending, and maintaining trust in a decentralized network
(d) Different types of consensus algorithms
Common consensus algorithms include Proof of Work (PoW), Proof of Stake (PoS), Practical Byzantine Fault Tolerance (PBFT), Delegated Proof of Stake (DPoS), and Raft consensus
(e) Consensus algorithm used in Hyperledger Fabric
Hyperledger Fabric uses PBFT-based consensus and Raft ordering service, which provides fault tolerance, faster transaction finality, and suitability for permissioned networks
(f) What is chaincode?
Chaincode is a smart contract in Hyperledger Fabric that defines business logic and rules for transactions on the blockchain network
(g) Two financial applications using blockchain
Examples include Bitcoin cryptocurrency and Ethereum-based smart contracts used in decentralized finance (DeFi) applications
(h) Blockchain in supply chain management with example
Blockchain provides transparency and traceability in supply chains.
Example: Tracking food products from farmers to consumers to ensure authenticity and reduce fraud
(i) Non-Fungible Tokens (NFTs) in land records
NFTs represent unique ownership of land assets. Blockchain-based NFTs can prevent land fraud by providing tamper-proof ownership records
(j) Security aspects of blockchain
Security aspects include cryptographic hashing, digital signatures, decentralization, immutability, and consensus-based validation of transactions
SECTION B
Attempt any THREE (10 × 3 = 30 marks)
(a) Key principles of blockchain for eliminating security threats
Key principles include decentralization, transparency, immutability, cryptographic security, consensus, and distributed verification. These principles prevent data tampering, unauthorized access, and single-point failures
(b) Major elements of blockchain ecosystem with example
The ecosystem includes nodes, blocks, transactions, consensus mechanisms, smart contracts, wallets, and miners/validators.
Example: In Bitcoin, miners validate transactions and add blocks to the chain
(c) Practical Byzantine Fault Tolerance (PBFT)
PBFT is a consensus algorithm designed to tolerate Byzantine faults. It works through phases—pre-prepare, prepare, and commit—to ensure agreement even if some nodes act maliciously. It is suitable for permissioned blockchains like Hyperledger Fabric
(d) Blockchain in insurance systems with example
Blockchain improves transparency and automation in insurance.
Example: Smart contracts automatically process claims when predefined conditions are met, reducing fraud and claim settlement time
(e) Architecture of digital identification system using blockchain
A blockchain-based digital ID system includes user identity data stored as cryptographic hashes, decentralized identity verification, and smart contracts for access control.
( In exam, draw architecture diagram showing user, blockchain, verifier)
SECTION C
Q3 (Attempt any one)
(a) Blockchain architecture and benefits of immutability
Blockchain architecture consists of data layer, network layer, consensus layer, incentive layer, and application layer.
Immutability benefits: prevents data tampering, ensures trust, enables auditability, and improves security in financial and government systems
(b) Block in blockchain and block size in Bitcoin & Ethereum
A block contains block header, transaction list, nonce, timestamp, and hash of previous block.
Bitcoin block size: ~1 MB
Ethereum block size: dynamic (gas-based)
Q4 (Attempt any one)
(a) Double spending in Bitcoin blockchain
Double spending refers to spending the same digital currency twice. Bitcoin prevents it using PoW consensus and confirmation of transactions through block validation
BLOCKCHAIN-ARCHITECTURE-DESIGN-…
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(b) Merkle root and its implementation
Merkle root is the top hash of a Merkle tree formed by hashing all transactions in a block. It ensures data integrity and efficient verification
Q5 (Attempt any one)
(a) Hyperledger Fabric and transaction validation policies
Hyperledger Fabric is a permissioned blockchain framework. Validation policies include endorsement policies, access control policies, and chaincode validation policies
(b) Hyperledger Composer and projects under Hyperledger
Hyperledger Composer is a tool for developing blockchain applications.
Projects include Fabric, Sawtooth, Indy, Iroha, and Besu
Q6 (Attempt any one)
(a) Fish supply chain use case using blockchain
Blockchain ensures traceability of fish from catch to consumer, prevents illegal fishing, and improves transparency in the supply chain
(b) Executing accounting and blockchain support
Executing accounting records transactions in real time. Blockchain supports it by providing transparent, immutable, and automated ledger systems
Q7 (Attempt any one)
(a) Blockchain in public distribution & social welfare systems
Blockchain ensures transparency, prevents corruption, and enables efficient delivery of subsidies and welfare benefits
(b) Security and privacy issues in blockchain
Issues include scalability, privacy leakage, smart contract vulnerabilities, key management risks, and regulatory challenges
