Topic 12: Computer & IT — Networks, Cloud, Blockchain & Digital India

Information technology is a very high-weight GS-III area linking science, economy & governance. This file covers computer basics (hardware, software, memory, generations), networks & the Internet (protocols, IP, WWW, 4G/5G/6G), cloud computing, Big Data & data centres, blockchain & cryptocurrency, cyber security & cyber attacks (malware, ransomware, phishing), digital public infrastructure (Aadhaar, UPI, ONDC), Digital India & e-governance, and data protection (DPDP Act) — with labelled diagrams, tables and real dated PYQs with full model answers. (AI & robotics are in Topic 13; supercomputers/quantum in Topic 14.)

UPSC Prelims · Mains GS-III Blockchain · 5G ~40 min read Cyber Security & DPI Very High CA Weight

1.Computer Basics
2.Networks & the Internet
3.Mobile Tech — 5G & 6G
4.Cloud Computing & Big Data
5.Blockchain & Cryptocurrency
6.Cyber Security
7.Digital Public Infrastructure
8.Digital India & e-Governance
9.Data Protection & Governance
10.Current Affairs Link
11.Prelims PYQs
12.Mains PYQs + Model Answers
★15-Minute Revision Box

Conceptual Clarity — How UPSC Tests Computers & IT

IT is a guaranteed, high-return area — almost every year has Prelims (blockchain, cloud, cyber terms) & Mains (cyber security, DPI, digital governance) questions. Sort your prep into three question-types:

Definitional / static — "what is cloud computing?", "what is blockchain?", "IP address vs protocol?". Recall of concepts & terms.
Statement-elimination — blockchain features, cyber-attack types, DPI components where one detail decides the answer.
Applied / current — a reform or incident in the news (DPDP Act, ransomware attack, UPI) linked to a fundamental — the strong GS-III governance bridge.

Highest-frequency themes: cloud & big data · blockchain/DLT · 5G · cyber security (malware, ransomware, phishing) · DPI (Aadhaar, UPI, ONDC) · Digital India · DPDP Act.

1. Computer Basics

Hardware = physical parts (CPU, memory, input/output); software = programs (system software like OS, and application software).
CPU (processor) = the "brain" — control unit + ALU (arithmetic logic unit). Computers work in binary (0s & 1s); a bit = 0/1, a byte = 8 bits.
Memory: primary (RAM = temporary/volatile, ROM = permanent) & secondary (hard disk, SSD, USB — permanent storage).
Generations: valves → transistors → integrated circuits → microprocessors → AI/parallel — each smaller, faster & cheaper (Moore's Law).

Prelims facts: computers use binary (0/1); bit = smallest unit, byte = 8 bits; RAM = volatile/temporary, ROM = non-volatile; CPU = control unit + ALU; Moore's Law = transistor count roughly doubles ~every two years.

2. Networks & the Internet

Fig 12.1 — The Internet is a global network of networks; devices communicate using protocols (rules like TCP/IP) and unique IP addresses. The Web (WWW) is a service running on the Internet.

Network = connected devices sharing data (LAN, WAN). The Internet = a global network of networks.
Protocols = agreed rules for communication (TCP/IP, HTTP/HTTPS); an IP address uniquely identifies a device; DNS translates names to IP.
WWW (Web) = a service of the Internet (webpages via HTTP); the Internet also carries email, streaming, etc.

Prelims traps: the Internet (infrastructure) is not the same as the WWW (a service on it); TCP/IP is the core protocol suite; an IP address identifies a device; DNS maps domain names to IP addresses.

3. Mobile Technology — 5G & 6G

Generation	Feature
2G / 3G	Voice & basic data / mobile internet
4G	High-speed broadband, video
5G	Very high speed & capacity, ultra-low latency — enables IoT, smart factories, remote surgery, autonomous vehicles
6G (future)	Even faster, AI-native, holographic & sensing; India's Bharat 6G vision

Prelims facts: 5G's key advances are ultra-low latency & massive device connectivity (IoT), not just speed; India has a Bharat 6G Vision for next-gen R&D. IoT = "Internet of Things" — everyday devices connected online.

4. Cloud Computing & Big Data

Cloud computing = using computing resources (storage, servers, software) over the Internet on demand, instead of owning them — pay-as-you-use. Models: IaaS, PaaS, SaaS.
Big Data = extremely large, fast, varied data sets (the "3 Vs": volume, velocity, variety) analysed for insights — powers AI, governance & business.
Data centres & edge computing (processing near the source) support cloud & IoT; data localisation is a policy issue.

Prelims traps: cloud = on-demand computing over the internet (IaaS/PaaS/SaaS); Big Data's 3 Vs = volume, velocity, variety; edge computing processes data near the source to cut latency. Data localisation = storing data within the country.

5. Blockchain & Cryptocurrency

Blockchain = a distributed, tamper-evident digital ledger — records (blocks) are chained & copied across many computers, so no single party controls it & entries can't be altered easily. A type of Distributed Ledger Technology (DLT).
Features: decentralisation, transparency, immutability, security via cryptography. Uses "consensus" (e.g. proof-of-work/stake) to validate.
Cryptocurrency (Bitcoin, etc.) is one use; others: smart contracts, supply-chain tracking, land records, digital identity.
CBDC: the RBI's Digital Rupee (e₹) is a central-bank digital currency — sovereign, unlike private crypto.

Prelims facts: blockchain = distributed, immutable ledger (a form of DLT); key traits = decentralisation, transparency, immutability; cryptocurrency is just one application; CBDC (Digital Rupee) is issued by the RBI, unlike private cryptocurrencies.

6. Cyber Security

Threat	What it is
Malware	Malicious software (virus, worm, trojan, spyware)
Ransomware	Locks/encrypts data & demands ransom (e.g. WannaCry)
Phishing	Fraud tricking users into revealing passwords/OTP
DDoS	Flooding a service to crash it
Data breach	Stealing/leaking sensitive data

India's framework: CERT-In (national cyber-incident response), NCIIPC (protects critical infrastructure), the Cyber Crime Coordination Centre (I4C) & the IT Act.
Concepts: encryption, firewalls, two-factor authentication, zero-trust; the "CIA triad" — Confidentiality, Integrity, Availability.

Prelims traps: ransomware encrypts & demands payment; phishing tricks users into sharing credentials; DDoS overwhelms a service. CERT-In is India's nodal cyber-response agency; NCIIPC protects critical information infrastructure.

7. Digital Public Infrastructure (DPI)

DPI = shared, open digital platforms (the "India Stack") that enable services at population scale — India is a global leader.
Identity: Aadhaar (biometric digital ID); Payments: UPI (instant interoperable payments) — among the world's largest; Data: DigiLocker, Account Aggregator.
ONDC (Open Network for Digital Commerce) & OCEN (credit) extend DPI to e-commerce & lending.

GS-III hook: DPI (Aadhaar + UPI + data) has powered financial inclusion, Direct Benefit Transfer, and a booming digital economy — a model India is exporting globally (a soft-power & development theme).

8. Digital India & e-Governance

Pillar / initiative	Aim
Digital infrastructure	Broadband (BharatNet), digital identity, mobile connectivity
e-Governance	Services online (DigiLocker, UMANG, e-courts, GeM procurement)
Digital empowerment	Digital literacy (PMGDISHA), local-language content
Direct Benefit Transfer	JAM trinity (Jan Dhan–Aadhaar–Mobile) for leak-proof subsidies

Prelims facts: Digital India (2015) aims to make India a digitally empowered society; JAM = Jan Dhan + Aadhaar + Mobile enabling DBT; BharatNet connects gram panchayats with broadband; GeM = Government e-Marketplace.

9. Data Protection & Governance

DPDP Act, 2023 (Digital Personal Data Protection) — India's data-protection law: consent-based processing, rights of "data principals", duties of "data fiduciaries", and a Data Protection Board.
Right to privacy is a fundamental right (Puttaswamy judgment, 2017) — the basis for data protection.
Issues: data localisation, surveillance vs privacy, cross-border data flows, and the digital divide.

GS-II/III hook: the digital economy needs both data-driven innovation and privacy protection. The DPDP Act 2023 operationalises the fundamental right to privacy (Puttaswamy, 2017) — balancing growth, security & individual rights.

10. Current Affairs Link (2024–2026)

IT is the most active governance-tech news area. Verify the latest before the exam. check for latest update or data

Data protection & AI rules: DPDP Act rules, data-governance & platform regulation apply Section 9. check for latest update or data

DPI & UPI globalisation: UPI going international, ONDC expansion & Digital Rupee pilots apply Sections 5–7. check for latest update or data

Cyber attacks: ransomware & data breaches on banks, health & infrastructure keep cyber security topical. check for latest update or data

Recent theme	Fundamental it tests	Why it matters for UPSC
DPDP Act rules	Data protection	GS-II/III rights & economy.
UPI / ONDC / e₹	DPI & blockchain	GS-III digital economy.
Ransomware / breaches	Cyber security	GS-III security.
5G / 6G roll-out	Mobile tech	GS-III infrastructure.

Recurring exam hooks: blockchain vs crypto vs CBDC · cloud & big data · cyber-attack types & CERT-In · DPI (Aadhaar/UPI/ONDC) · DPDP Act · 5G.

11. Prelims PYQs

Objective questions anchored to genuinely tested UPSC themes on computers & IT. Each carries a worked rationale.

UPSC Prelims — Blockchain

Q: Which of the following best describes blockchain technology?

(a) A centralised database controlled by a bank
(b) A distributed, tamper-evident digital ledger
(c) A type of computer virus
(d) A cloud storage service

Answer: (b) Blockchain is a distributed, immutable ledger copied across many nodes (a form of DLT); cryptocurrency is only one of its applications.

UPSC Prelims — Digital Rupee

Q: The Digital Rupee (e₹) launched in India is a —

(a) private cryptocurrency
(b) central bank digital currency (CBDC)
(c) stablecoin issued by banks
(d) mobile wallet app

Answer: (b) The Digital Rupee is a CBDC issued by the RBI — sovereign legal tender in digital form, unlike private cryptocurrencies.

UPSC Prelims — Cloud

Q: "Cloud computing" essentially means —

(a) weather forecasting by computers
(b) using computing resources over the internet on demand
(c) wireless charging
(d) a type of satellite

Answer: (b) Cloud computing delivers storage, servers & software over the internet on a pay-as-you-use basis (IaaS/PaaS/SaaS), avoiding owning hardware.

UPSC Prelims — Cyber threats

Q: Ransomware is a type of cyber attack that —

(a) encrypts a victim's data and demands payment to release it
(b) floods a website with traffic to crash it
(c) steals data silently over years
(d) physically damages hardware

Answer: (a) Ransomware encrypts/locks data and demands a ransom (e.g. WannaCry). Flooding a site is DDoS; tricking users for credentials is phishing.

UPSC Prelims — Cyber agency

Q: CERT-In is India's nodal agency for —

(a) issuing Aadhaar
(b) responding to cyber-security incidents
(c) regulating telecom tariffs
(d) approving software patents

Answer: (b) CERT-In (Indian Computer Emergency Response Team) is the national agency for cyber-incident response; NCIIPC protects critical information infrastructure.

UPSC Prelims — Internet vs Web

Q: The World Wide Web (WWW) is —

(a) the same as the Internet
(b) a service that runs on the Internet
(c) a type of cable
(d) a search engine

Answer: (b) The Internet is the underlying global network; the WWW is one service (webpages via HTTP) running on it, alongside email, streaming, etc.

UPSC Prelims — DPI

Q: UPI (Unified Payments Interface) is best described as —

(a) a cryptocurrency
(b) an instant interoperable digital-payment system
(c) a data-storage standard
(d) a mobile network

Answer: (b) UPI enables instant, interoperable bank-to-bank payments via mobile — a pillar of India's Digital Public Infrastructure (India Stack).

UPSC Prelims — Data law

Q: The DPDP Act, 2023 deals primarily with —

(a) cyber warfare
(b) protection of digital personal data
(c) spectrum allocation
(d) e-commerce taxation

Answer: (b) The Digital Personal Data Protection Act, 2023 governs consent-based processing of personal data, giving rights to individuals & duties to data fiduciaries, backed by the right to privacy (Puttaswamy, 2017).

Prelims — anticipated themes

Likely: blockchain vs crypto vs CBDC · cloud & big data 3 Vs · cyber-attack types & CERT-In · DPI (Aadhaar/UPI/ONDC) · DPDP Act & privacy · 5G/IoT · internet vs web. check for latest update or data

12. Mains PYQs + Model Answers

IT anchors GS-III questions on cyber security, digital economy & governance. The frameworks below show how to deploy it analytically.

Mains GS-III 15 marks · 250 words

Q: Cyber security is central to national security in the digital age. Discuss the threats and India's preparedness.

Model Answer

Introduction: As governance, economy & defence digitise, cyber security (Section 6) becomes core to national security.
Threats:
- Ransomware & malware on banks, health & power; phishing & data breaches; attacks on critical infrastructure; state-sponsored & supply-chain attacks.
India's preparedness: CERT-In, NCIIPC, I4C, the IT Act & DPDP Act, a National Cyber Security Policy & cyber commands.
Gaps: skilled manpower, awareness, outdated systems, coordination & a dedicated cyber-security law.
Way forward: resilient infrastructure, capacity building, public-private cooperation & international norms.
Conclusion: cyber resilience is now inseparable from national security & economic stability.

Mains GS-III 15 marks · 250 words

Q: Digital Public Infrastructure has transformed governance & the economy in India. Examine.

Model Answer

Introduction: DPI (Section 7) — the India Stack of digital identity, payments & data — delivers services at population scale.
Governance impact:
- Aadhaar-enabled DBT & JAM cut leakages; UPI & digital services widen access & formalise the economy.
Economic impact: financial inclusion, fintech growth, ONDC-enabled e-commerce & a globally exported model.
Concerns: privacy & data protection (DPDP Act), exclusion errors, digital divide & cyber risk.
Way forward: inclusive design, grievance redress, robust privacy & cyber security.
Conclusion: DPI is a powerful tool for inclusive, efficient governance if rights & access are safeguarded.

Mains GS-III 10 marks · 150 words

Q: Distinguish between blockchain, cryptocurrency and a central bank digital currency (CBDC).

Model Answer

Introduction: These are related but distinct (Section 5).
Distinctions:
- Blockchain = the underlying distributed-ledger technology; cryptocurrency = a private digital asset built on it; CBDC = sovereign digital currency issued by the central bank.
Key contrast: crypto is decentralised & volatile; CBDC (Digital Rupee) is state-backed legal tender.
Conclusion: blockchain is the tech; crypto & CBDC are different applications with very different trust models.

Mains GS-III 15 marks · 250 words

Q: Balancing data-driven innovation with the right to privacy is a key challenge. Discuss with reference to the DPDP Act.

Model Answer

Introduction: The digital economy runs on data, but data use can violate privacy — a fundamental right (Puttaswamy, 2017).
The tension:
- Data powers AI, DPI & services; unchecked use risks surveillance, profiling & breaches.
DPDP Act 2023: consent-based processing, data-principal rights, fiduciary duties & a Data Protection Board (Section 9).
Challenges: wide government exemptions, localisation, enforcement capacity & cross-border flows.
Way forward: strong independent regulator, privacy-by-design & clear limits on state access.
Conclusion: well-designed data law can enable innovation while protecting citizens' rights.

Mains GS-III — anticipated themes

Likely: cyber security & national security · DPI & digital economy · blockchain applications beyond crypto · data protection vs privacy · 5G/IoT & digital divide. check for latest update or data

15-Minute Revision Box

Must-Remember Facts — Computer & IT

Basics & networks:

Binary (0/1); bit vs byte (8 bits); RAM volatile, ROM permanent
CPU = control unit + ALU; Moore's Law
Internet ≠ WWW (web = service on internet); TCP/IP, IP address, DNS
5G = low latency + IoT; Bharat 6G vision

Cloud, big data, blockchain:

Cloud = on-demand computing (IaaS/PaaS/SaaS)
Big Data 3 Vs = volume, velocity, variety
Blockchain = distributed immutable ledger (DLT); crypto = one use
Digital Rupee (e₹) = RBI CBDC, not private crypto

Cyber security:

Ransomware = encrypt + demand; phishing = trick for credentials; DDoS = flood
CERT-In = cyber response; NCIIPC = critical infra
CIA triad = Confidentiality, Integrity, Availability

DPI & governance:

India Stack: Aadhaar (ID) + UPI (payments) + data (DigiLocker/AA)
ONDC = open e-commerce; JAM = Jan Dhan+Aadhaar+Mobile (DBT)
Digital India (2015); BharatNet; GeM
DPDP Act 2023; privacy = FR (Puttaswamy 2017)

Highest-frequency themes: blockchain/CBDC · cloud & big data · cyber-attack types & CERT-In · DPI (Aadhaar/UPI/ONDC) · DPDP Act · 5G.

Term	Meaning
Cloud	On-demand compute
Blockchain	Distributed ledger
CBDC	e₹ by RBI
UPI	Instant payments

Threat	Action
Ransomware	Encrypt+ransom
Phishing	Steal creds
DDoS	Flood service
Malware	Malicious code

Topic 12: Computer & IT — Networks, Cloud, Blockchain & Digital India

On this page

Conceptual Clarity — How UPSC Tests Computers & IT

1. Computer Basics

2. Networks & the Internet

3. Mobile Technology — 5G & 6G

4. Cloud Computing & Big Data

5. Blockchain & Cryptocurrency

6. Cyber Security

7. Digital Public Infrastructure (DPI)

8. Digital India & e-Governance

9. Data Protection & Governance

10. Current Affairs Link (2024–2026)

11. Prelims PYQs

12. Mains PYQs + Model Answers

Model Answer

Model Answer

Model Answer

Model Answer

15-Minute Revision Box

Must-Remember Facts — Computer & IT