(SEM VI) THEORY EXAMINATION 2024-25 BLOCKCHAIN ARCHITECTURE DESIGN

BCS063 – BLOCKCHAIN ARCHITECTURE DESIGN

Time: 3 Hours | Max Marks: 70

SECTION A – Short Answer Questions

(2 × 7 = 14 marks | Attempt ALL)
Write definition + 1–2 clear points

a. Purpose of Cryptographic Hash Function in Blockchain

A cryptographic hash function converts input data into a fixed-length output.
It ensures data integrity, immutability, and tamper detection in blockchain blocks.

b. Any Two Blockchain Design Primitives

Cryptographic hash functions                         Digital signatures
(Other examples: Merkle trees, consensus mechanisms)

c. Two Scalability Challenges in Blockchain                       Limited transactions per second (TPS)

Increased latency due to consensus and block size limits

d. Two Major Limitations of Proof of Work (PoW)

Very high energy consumption                                          Low scalability and slow transaction confirmation

e. Chaincode vs Traditional Smart Contracts

Chaincode (Hyperledger Fabric) runs in a permissioned environment, supports multiple languages, and follows an endorsement policy, unlike public blockchain smart contracts which are open and permissionless.

f. Blockchain for Traceability & Transparency in Supply Chain

Provides an immutable record of product movement        Enables real-time tracking and reduces fraud

g. Digital Identity in Government: One Benefit & One Risk

Benefit: Secure and tamper-proof citizen records          Risk: Privacy concerns if data governance is weak

SECTION B – Medium Answer Questions

(7 × 3 = 21 marks | Attempt ANY THREE)
 Write concept → explanation → example

a. Basic Cryptographic Primitives in Blockchain

Hash functions: Data integrity                                   Public-key cryptography: Authentication

Digital signatures: Transaction verification                Example: SHA-256, RSA, ECDSA.

b. Permissioned Blockchain Consensus vs Public Blockchain

Permissioned blockchains use PBFT, Raft, or Kafka, which are faster, energy-efficient, and scalable compared to PoW-based public blockchains.

c. Chaincode Development & Deployment in Hyperledger Fabric

Steps:                                                                             Write chaincode

Package chaincode                                                        Install on peers

Approve by organizations                                             Commit to channel
Ensures controlled execution and validation.

d. Impact of Blockchain in Financial Services                Faster settlement

Reduced intermediaries                                                Improved transparency
Used in capital markets, insurance, and payments.

e. Blockchain in Government Infrastructure: Challenges & Solutions

Challenges: Scalability, legal framework, integration
Solutions: Permissioned networks, regulations, pilot projects

SECTION C – Attempt ANY ONE

(7 marks)

a. Evolution from Digital Currency to Blockchain

Digital currencies led to distributed ledgers to remove intermediaries.
Blockchain combined cryptography + consensus + decentralization, forming a secure transaction system.

b. Permissioned vs Permissionless Blockchain