# Blockchain Technology Bootcamp What is Blockchain ? Blockchain is simply a decentralised distributed ledger that records transactions across many computers. # How Blockchain Works 1. Many Computers Connect: A network of computers (nodes) is created. 2. Transaction Occur : Someone sends or receives 3. The nodes check if the transaction is valid. 4. Transactions are Grouped: Valid transactions are collected into a block 5. Each block is connected to the previous one, creating a chain. 6. The nodes agree that the blockchain is accurate. 7. Each node updates its copy of the blockchain. # Key Concept of Blockchain 1. Decentralization: Blockchain is a decentralized system, meaning no single entity controls it. 2. Immutable: Blockchain is an immutable ledger, meaning once a transaction is recorded, it cannot be altered. 3. Consensus: Blockchain nodes reach a consensus on the state of the blockchain, ensuring its accuracy and integrity. 4. Transparency: All transactions on the blockchain are recorded publicly and can be viewed by anyone. 5. Security: Blockchain uses advanced cryptography to secure transactions and control access. # Web3 What is web3 ? Web3 is the next evolution of the internet built on blockchain technology which focuses on decentralisation and user ownership. it enables peer to peer interactions without intermediaries. The Web evolution and differences Web1 ( 1990s - Early 200s ) Read only static website Oneway-information flow Users are consumers of content Web2 ( 2000s - Present ) Interactive social platform User-generated content Categorised, control by big tech companies Web3 ( Emerging ) User owned internet Decentralised application Data ownership and control # Node A node is a computer that is connected to the blockchain network and keeps a copy of the blockhain data. The node ensures the validity of transactions on the network The node verify the validity of new blocks before it's added to the blockchain The node store a copy of the ethereum blockchain data The node execcutes smart contracts The node shares data with other nodes on the blockchain # Ethereum Virtual Machine What is EVM ? The Ethereum Virtual Machine is a computer that is operated by all the nodes that contribute to it. It is basically a virtual computer that specializes in processing smart contract transactions. Features of an EVM on Ethereum Network The EVM execute smart contract on the network. It's also ensures and verify smart contract execute correctly . The EVM measure the gas consumption of smart contracts . It ensures smart contract execution are reflected on the blockchain to maintain integrity of the network. The EVM interprete bytecode generated by compiling smart contract written in high level languages like solidity for ethereum. # Gas what is Gas ? Gas is a unit of computational measurement required to execute a transaction or smart contract on the ethereum network. Some Importance of Gas on the ethereum network Gas is paid to validators for processing transactions and executing smart contract. The gas decreases network vulnerability to attack. The gas regulate number of transactions to be processed at a given time. The gas also prevent network spamming which maintain network stability. # Block What is Block ? A block is like a container that contains a collection of transactions and other data which has a unique code called hash that is linked to the previous block on the blockchain. The block contains: The Block Hash Block number Transaction Hash Timestamp Validator address Gas used Gas limit Parent Hash # Wallet What is a wallet ? A wallet is a software or device that allows you interact with the blockchain. It allows you to store, send and receive cryptocurrencies. The wallet consists of a Public Key (Address) which is a unique identifier that lets others send you cryptocurrencies. The wallet also has Private Key which is a secret code that only you know, used to sign transactions and control your funds.