Blockchain Fundamentals | Anish | Gurzu

What is the much talked about blockchain technology? How does it work and where is it used?
In this episode of knowledge ketchup, Anish educates about the basics of blockchain technology.

Transcript

1. Blockchain Fundamentals Anish Shrestha 2025/10/29
2. 01 What is Blockchain? 02 How Blocks Link 03 Network Mechanics 04 Ethereum Smart Contracts 05 Real-World Impact
3. What is Blockchain? PART 01
4. Blockchain — Key Terms at a Glance Term Definition Example Block A data structure that contains a list of verified transactions, timestamp, and hash. Block #800,000 on Bitcoin Transaction A record of value transfer or smart contract interaction on the blockchain. Sending ETH to another wallet Gas / Gas Fee Transaction fee paid to incentivize validators or miners to process and confirm transactions. ETH gas fee for swaps Node Any computer connected to the blockchain network (distributed system) that validates and stores transaction data. Bitcoin full node, Ethereum client Miner / Validator Participants who confirm transactions and add new blocks to the blockchain. Bitcoin miners, Ethereum validators Wallet Address A unique public identifier used to send or receive crypto assets. 0xABC123...
5. What is Blockchain? Decentralized Database Blockchain operates as a decentralized database, with identical copies of the ledger stored across thousands of nodes. No Single Control Ensures no single entity controls the data, promoting transparency and trust. Shared Digital Ledger A shared, immutable record of all transactions across the network.
6. How Blocks Link PART 02
7. Inside a Block Header The block header contains critical information that ensures the integrity and security of the blockchain. Previous Block Hash A cryptographic link to the previous block, making the blockchain tamper-evident. Merkle Root A summary of all transactions in the block for efficient validation. Timestamp & Nonce Used in mining to create a valid, unique, and secure block.
8. Source: Blockchain.com
9. Hash Pointers Glue the Chain Each block contains a cryptographic hash of the previous one, creating an unbreakable chain. BLOCK #100 Hash: 0000abcd... Hash Link BLOCK #101 Prev Hash: 0000abcd... Hash: 0000def0... Hash Link BLOCK #102 Prev Hash: 0000def0... Hash: 0000f123... Any alteration in a block would change its hash, breaking the chain and signaling tampering.
10. Network Mechanics PART 03
11. The Transaction Journey 1. Initiation User signs transaction with private key and broadcasts it. 2. Validation Nodes validate the signature and check funds. 3. Broadcasting Transaction is relayed to all other nodes. 4. Inclusion Miners include it in a block, finalizing the record.
12. Consensus Secures History Different methods are used to achieve agreement across the network on the state of the blockchain. Proof of Work (PoW) Miners compete to solve complex cryptographic puzzles. The first to solve it gets to add the next block. Security through computational effort. Proof of Stake (PoS) Validators are chosen based on the amount of cryptocurrency they hold and are willing to 'stake' as collateral. Security through economic incentives.
13. Ethereum Smart Contracts PART 04
14. Ethereum Smart Contracts Code Becomes Law Smart contracts are immutable scripts deployed on the blockchain. They execute deterministically when triggered by a transaction, automating agreements without intermediaries. Immutable Scripts Once deployed, the code cannot be altered, ensuring integrity. Deterministic Execution Given the same inputs, they always produce the same results.
15. Smart Contract Deployment Workflow 1. Compilation Solidity code is compiled into bytecode. 2. Signing Bytecode is signed with the developer's key. 3. Broadcasting Transaction is broadcast to the network. 4. Address Assignment Contract is assigned a deterministic address.
16. Quick Example Remix IDE A popular, open-source Integrated Development Environment (IDE) used for writing, compiling, and debugging Solidity smart contracts before deployment. Key Features: In-browser development Built-in compiler & debugger • Direct deployment to testnets Figure: Example Flowchart of a Smart Contract — Try It Yourself
17. Real-World Impact PART 05
18. Real-World Impact: Finance Transformed Programmable Money Stablecoins enable fast, secure, and transparent transactions without traditional financial intermediaries. Decentralized Exchanges DEXs allow users to trade directly from their wallets, reducing counter-party risk and providing 24/7 global access. Global Markets Blockchain enables continuous, inclusive financial markets accessible to anyone with an internet connection.
19. Beyond Currency Blockchain's impact extends far beyond finance, revolutionizing how we track goods, own digital assets, and organize ourselves. Supply Chain Provenance Tracks goods from origin to destination, ensuring authenticity for items like diamonds and pharmaceuticals. NFTs & Digital Ownership Grants verifiable ownership of digital assets, creating new business models in art and gaming. DAOs & Governance Enables decentralized governance, allowing global teams to collaborate without traditional hierarchies.
20. Cross-Industry Applications Blockchain provides secure and transparent solutions for a wide range of sectors. Healthcare Securely share patient data and manage pharmaceutical supply chains. Insurance Automate claims processing and reduce fraud with transparent records. Internet of Things Enable secure, autonomous machine-to-machine transactions and data sharing.
21. Key Takeaways Blockchain is a foundational technology for digital trust, built on several core principles. Decentralization No single point of control or failure. Immutability Data, once written, cannot be changed. Consensus Agreement on the state of the ledger is achieved cryptographically. Automation Smart contracts enable self-executing agreements.
22. THANK YOU ! DISCLAIMER Cryptocurrency activities are currently illegal in Nepal as per Nepal Rastra Bank regulations.