Part 1 of 3

BUIDL the Chain

Introduction to Blockchain

Blockchain Club • February 12, 2026

The ₹1 Billion Question

Why can't someone just edit a bank's database and give themselves ₹1 billion?

Banks have security, right?
Passwords, firewalls, encryption...
But who controls the database?
What if the person with admin access is the one editing it?

2 / 30

The Real Problem: Trust

In centralized systems, we trust an authority:

Banks to maintain accurate records
Governments to maintain fair registries
Platforms to keep our data safe

But what if that authority:

Makes a mistake?
Gets hacked?
Becomes corrupt?
Simply changes the rules?

3 / 30

Real Example: India's Land Records Problem

Scenario: Government office maintains land ownership records
An official with admin access quietly changes:
Farmer A's plot → Builder B's property
Nobody notices for months
By then, Builder B has already constructed on it
Who do you trust now?

This is why Andhra Pradesh & Haryana piloted blockchain land registries

4 / 30

BUIDL the Chain — 3-Part Series

TODAY

Part 1: Introduction to Blockchain

Why it exists, how it works, the philosophy behind it

PART 2

Smart Contracts & Blockchain Dev Tools

Solidity, APIs, building on-chain

PART 3

Blockchain in the Real World

NFTs, Bitcoin culture, markets, scams & society

5 / 30

Today's Agenda (60 minutes)

1. Why blockchain exists — the trust problem it solves
2. How blocks, hashes, and chains make data tamper-proof
3. Decentralization, consensus, and distributed authority
4. Blockchain vs. Traditional Databases
5. The 2008 crisis and Bitcoin's origin story
6. Real-world use cases and the future vision

6 / 30

Distributed ≠ Decentralized

DISTRIBUTED

Components on different networked computers
Working toward a common goal
Example: Netflix CDN
BUT: Netflix controls ALL

DECENTRALIZED

Decision-making distributed among participants
NO central authority
Example: Bitcoin
Result: Nobody controls all

Decentralized systems are a SUBSET of distributed systems!

7 / 30

Quick Check: Is Google Drive Decentralized?

Your files are stored on servers worldwide...

✓ Is it DISTRIBUTED? Yes

Files replicated across multiple data centers
Redundancy for reliability

✗ Is it DECENTRALIZED? No

Google controls every server
Google can read your files
Google can delete your account

8 / 30

Key Differences

Dimension	Distributed	Decentralized
Control	One organization	Shared among participants
Central Services	May rely on them	Minimizes reliance
Point of Failure	Can have single points	Eliminates them
Data & Privacy	Centrally managed	User-distributed

🎮 Try it: Classify real systems as distributed or decentralized →

9 / 30

Disintermediation: Removing Middlemen

Traditional (India → USA):

You → Bank → SWIFT → US Bank → Friend

Takes 2-5 days
Fees: ₹500-2000
Can be blocked/delayed

Bitcoin:

You → Bitcoin Network → Friend

~10-60 minutes
Fee: Usually < ₹100
Unstoppable

10 / 30

Healthcare Example

Current (Centralized)

Hospital controls your records
Switch hospitals = New doctor can't access old records
You don't own your medical history

Decentralized

YOU own your data on blockchain
Grant access to any doctor
Records are portable & tamper-proof

Already piloted in Estonia & UAE

11 / 30

The Google Sheets Analogy

Think of blockchain like a Google Sheet shared across 1000s of computers...

But with 3 critical differences:

APPEND-ONLY

You can only add new rows, never edit/delete old ones

CRYPTO-LINKED

Each row contains a fingerprint (hash) of the previous row

CONSENSUS

Before a new row is accepted, majority must agree it's valid

12 / 30

Immutability: The Chain of Hashes

Every block has a cryptographic HASH (digital fingerprint)
Tiny change in data → Completely different hash
Each block stores the hash of the PREVIOUS block
Block 100 → Block 101 → Block 102 → ...
If you alter Block 100:
- Its hash changes
- Breaks the link to Block 101
- Breaks Block 102, 103, 104...

To 'get away with it', you'd need to recompute ALL blocks faster than the network adds new ones → Computationally impossible!

🎮 Try it: Break a blockchain and see what happens →

13 / 30

Your Node vs. The Network

Traditional DB

You own the server = You are God
Edit, delete, rewrite history
If everyone trusts it → Your edit becomes 'truth'

Blockchain Node

You own a node
Try to edit a block
Your version ≠ 1000s of other nodes
Network rejects your chain

The network enforces truth, not a single authority

14 / 30

Consensus: How the Network Agrees

                    PROOF OF WORK (Bitcoin)
                    Miners compete to solve computational puzzles
Winner adds next block + gets reward
Cost of cheating: Massive electricity & hardware

                

PROOF OF STAKE (Ethereum)

Validators stake cryptocurrency as collateral
Selected to propose blocks based on stake
If they cheat → Stake gets slashed

Goal: Make cost of attacking > reward of attacking

15 / 30

The 51% Attack

Theoretical vulnerability: If someone controls >50% of network power, they COULD manipulate the chain

Why it rarely happens on big networks:

Bitcoin: Would need >$10 billion in mining hardware
Ethereum: Would need >$20 billion in staked ETH
Even if you succeed, the attack crashes the coin's value
You destroy the value of what you spent billions to attack!

Large networks: Economically secure

Small networks: Vulnerable

16 / 30

Blockchain vs. Traditional Database

Attribute	Traditional Database	Blockchain
Control	Single admin/authority	Distributed across nodes
Data Modification	Full CRUD (edit, delete)	Append-only, immutable
Speed	Thousands - millions TPS	Limited (15-30 TPS on L1)
Trust Model	Trust the administrator	Trust the protocol/math
Best For	Dynamic data, complex queries	Audit trails, tamper-proof records

17 / 30

When to Use Blockchain?

Blockchain is NOT a replacement for databases. It's a specialized tool for when trust is the bottleneck.

Use Blockchain If:

Need immutability
No trusted central party
Multiple parties need access
Audit trail is critical
Censorship resistance needed

Use Database If:

High throughput needed
Trusted admin exists
Need to update/delete data
Complex queries required
Privacy over transparency

18 / 30

SECTION

The 2008 Crisis

Why Bitcoin Was Created

The 2008 Financial Crisis — Three Layers of Failure

Layer 1: Opacity within the system

Banks bundled risky mortgages into CDOs, got AAA ratings despite being junk, used off-balance-sheet entities to hide risk

Layer 2: The rule-changers changed the rules

When reckless bets failed, government bailed out banks with $700B TARP + $4.5T in QE (money printing)

Layer 3: Currency debasement as hidden tax

Creating trillions in new money diluted everyone's savings. Banks got rescued, citizens paid through inflation

20 / 30

What Made Banks "Too Big to Fail"?

Why didn't the government just let them die?

Interconnected dominoes: Banks owed each other trillions in derivatives. One failure = chain reaction across entire system
The Lehman experiment: Government DID let one bank fail (Lehman Brothers, Sept 2008). Result:
- Credit markets froze globally
- $300B withdrawn from money market funds in days
- ATMs and payroll systems at risk
The choice: Let banks fail = economic collapse vs. Bail them out = invisible inflation tax

21 / 30

Satoshi Nakamoto's Response

"The root problem with conventional currency is all the trust that's required to make it work. The central bank must be trusted not to debase the currency, but the history of fiat currencies is full of breaches of that trust."

— Satoshi Nakamoto, Feb 11, 2009

Bitcoin Genesis Block (Jan 3, 2009):

"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"

This headline was embedded in Bitcoin's first-ever block — a timestamp AND a political statement.

22 / 30

Bitcoin's Three-Layered Critique

1. Inner Ring: Opacity

"Data was technically public, but complexity was so extreme even regulators couldn't see real risk. Transparency without comprehensibility is NOT real transparency."

2. Middle Ring: Moral Hazard

"When you know the government will bail you out, you take bigger risks. The rules were changed AFTER the game was lost."

3. Outer Ring: Monetary Sovereignty

"Government can print money — until it's used to socialize losses while privatizing profits. Bitcoin removes that lever entirely."

23 / 30

Bitcoin's Design Responses

To opacity: Fully transparent, publicly auditable ledger. Monetary policy visible in source code.
To rule-changing: Rules enforced by code across thousands of nodes. No entity can decide to "bail out" a participant or change issuance.
To currency debasement: Fixed supply of 21 million coins. Halving every ~4 years. No central authority can create more.

Bitcoin removes the ability of any single authority to change the rules of money itself

🎮 Try it: Compare traditional banking vs DeFi →

24 / 30

SECTION

The Bigger Vision

Beyond Money

Full Ecosystem Decentralization

Blockchain isn't just about money. The vision is to decentralize EVERYTHING:

Communication

Mesh networks, decentralized messaging (Whisper protocol)

Storage

IPFS, Filecoin, Arweave — files distributed across network

Computing

Decentralized cloud computing, serverless functions

Identity & Wealth

Self-sovereign identity, tokens, DeFi

26 / 30

Web 1 → Web 2 → Web 3

Web 1 (1990s-2000s): Read

Static pages, you could only consume content

Web 2 (2000s-2020s): Read-Write

Social media, user-generated content
BUT: Platforms own your data (Facebook, Google, Instagram)

Web 3 (2020s+): Read-Write-Own

Decentralized, users own their data and digital assets
Vision: Own your content like you own physical property

27 / 30

Key Takeaways

Blockchain solves a trust problem, not a speed problem

Immutability through cryptographic hashing makes tampering impossible

Decentralization removes single points of failure and authority

Consensus mechanisms make attacks economically irrational

Bitcoin emerged as response to 2008 financial crisis — distrust of institutions

The vision extends beyond money — decentralizing everything

28 / 30

What's Next?

PART 2

Smart Contracts & Blockchain Dev Tools

Learn how to write code that runs on blockchain, deploy contracts, use APIs

PART 3

Blockchain in the Real World

NFT culture, market dynamics, recognizing scams, social impact

Continue learning, stay curious, and always verify!

Questions?

29 / 30

Thank You!

Blockchain Club

Register for Parts 2 & 3

https://tally.so/r/2ENvvj