## Why Has Blockchain Been Popular for So Long? The Technical Principles Are Actually Not That Complex

Have you ever wondered why blockchain has garnered so much attention? Honestly, it’s not because it’s trendy or makes people rich. It’s because it solves real problems — trust and data security.

## What Is Blockchain? Think Simply

Forget the complexity for now. Blockchain (Blockchain) is simply a **digital ledger that no one can cheat**.

Imagine this: instead of a single bank holding our accounts, everyone in the network keeps a copy. If someone tries to tamper with it, the other copies will show it’s wrong and reject it immediately. That’s the magic of blockchain.

## Let’s Look at How It Actually Works

Blockchain operates on three main interconnected principles:

### First: Hash Codes — "Fingerprints" of Data

Each block (Data) has a unique identifier called **Hash (Hash)** — like a fingerprint, no two are alike.

Each block has three components:
- **Data (Data)**: For example, Bitcoin stores transaction details — who sent, who received, how much.
- **Hash (Hash)**: The block’s own identifier. Changing even one piece of data changes the hash completely.
- **Previous Block Hash (Previous Hash)**: A link to the previous block.

For example, in Bitcoin:
- Block 1: Hash A24 contains 5 BTC from Golf → Poo, referencing previous block 000.
- Block 2: Hash 12B contains 3 BTC from Poo → Mali, referencing A24.
- Block 3: Hash 5C3 contains 2 BTC from Mali → Faa, referencing 12B.

See? Each block links to the next like a chain. If someone tampers with block 1, its hash changes, which makes block 2 invalid, which then invalidates block 3... making it very hard to manipulate.

### Second: Consensus — "Agreement"

Besides hashes, blockchain uses a system called **Consensus (Consensus)** as a safeguard.

Bitcoin uses **Proof-of-Work (PoW)** — a system that requires solving complex math problems to create a new block. It takes about 10 minutes and consumes enormous computational power.

Why do this? Because if someone wants to hack, they must solve the math problems for all previous blocks before adding a new one, which is extremely difficult.

### Third: P2P Network — "No Boss"

Blockchain has no single central authority. Instead, it uses a **Peer-to-Peer (P2P)** network.

When someone runs the software, they become a **Node (Node)** — storing data for the entire network and verifying transactions.

Steps to add a new block:
1. The new block is broadcast to all nodes.
2. Each node verifies the data.
3. When the majority agree, the new block becomes part of the chain.

**Summary**: To hack, you’d need to tamper with the entire chain + solve all the math problems + control over more than 51% of the network, which is practically impossible.

## There Are Different Types of Blockchain for Different Purposes

Currently, blockchain is divided into four main types, chosen based on needs:

### Public Blockchain (Public)
- **Features**: Open to everyone, permissionless, highly transparent
- **Examples**: Bitcoin, Ethereum, Solana
- **Advantages**: Security, transparency, democracy
- **Disadvantages**: Slow, energy-intensive
- **Use Cases**: Crypto trading, DeFi, open-source projects

### Private Blockchain (Private)
- **Features**: Closed, controlled by a single organization, efficient
- **Examples**: Hyperledger Fabric, MultiChain
- **Advantages**: Fast, secure, efficient
- **Disadvantages**: Risk of internal control
- **Use Cases**: Corporate, banking, internal logistics

### Hybrid Blockchain (Hybrid)
- **Features**: Mix of private and public
- **Examples**: XinFin, IBM Blockchain Platform
- **Advantages**: Flexible, balanced control and transparency
- **Disadvantages**: Complex management
- **Use Cases**: Financial systems, healthcare with strict regulation

### Consortium Blockchain (Consortium)
- **Features**: Controlled jointly by multiple organizations
- **Examples**: Corda by R3
- **Advantages**: Risk sharing, no single organization has total power
- **Disadvantages**: Requires coordination
- **Use Cases**: Supply chains, interbank, cross-industry collaborations

## Benefits of Blockchain? Plenty!

### 1. Increased Security
Encrypted data cannot be deleted, edited, or altered. This is a game-changer for data security.

### 2. Transparency and Verifiability
No single boss. Everyone can see transactions, making fraud impossible — something never achieved before.

### 3. Lower Costs
No intermediaries = no middleman fees. Pay only transaction fees. Much cheaper.

### 4. Traceability
Want to know where data or goods come from? Trace back through the chain.

### 5. Speed and Automation
No need to wait for many people to verify. Automated operation with high efficiency.

## Drawbacks of Blockchain? Still There

### 1. Limited Capacity — Not suitable for high-volume transactions
Bitcoin currently handles only about 7 transactions per second; Ethereum around 15. Visa processes 24,000 per second... a huge gap. But technology is evolving.

### 2. Theoretically Hackable
"51% Attack" — if someone controls over 51% of the network, they can manipulate it. But in practice? Nearly impossible.

### 3. Energy Consumption
Proof-of-Work requires powerful computers and consumes a lot of electricity. Some projects are shifting to Proof-of-Stake, which is more energy-efficient.

### 4. No Clear Regulations Yet
Until now, no international organization has set clear rules (Regulation). This causes ongoing confusion.

## Where Is Blockchain Actually Used?

Today, blockchain is not just theoretical:

### 1. Finance
Thailand’s central bank has a project called "Inthanon" developing a digital Baht using blockchain to replace the traditional Baht system. JMART uses JFIN for customer accounts and credit scoring for online loans.

### 2. Supply Chain
IBM created Food Trust Blockchain for consumers to trace raw materials back to their sources. Other companies use it to verify shipments and origins, impossible to counterfeit.

### 3. Voting Systems
Blockchain can create secure, transparent, and tamper-proof voting systems, reducing verification costs.

## Continue to the World of Web3

Blockchain is not just a trendy tech; it’s a serious tool to solve trust and data security issues. Despite limitations, development continues steadily. The future isn’t far off when blockchain becomes commonplace in everyday life.