Blockchain Demo

Blockchain is a decentralized, distributed ledger technology that records transactions across many computers so that the record cannot be altered retroactively without the alteration of all subsequent blocks.

Web3 represents the next evolution of the internet, built on decentralized technologies like blockchain. It aims to create a more open, trustless, and permissionless web ecosystem.

A P2P (Peer-to-Peer) network is a crucial component of blockchain technology. In a blockchain P2P network:

• Each node (computer) in the network acts as both a client and a server
• All nodes are equal and share the responsibility of storing and validating the blockchain
• New transactions and blocks are broadcast to all nodes in the network
• This decentralized structure enhances security and eliminates single points of failure

Mining is the process of adding new blocks to the blockchain. Miners:

• Collect and verify pending transactions
• Solve complex mathematical problems (Proof of Work)
• Create new blocks and add them to the blockchain
• Are rewarded with cryptocurrency for their efforts

Proof of Work is a consensus mechanism used in many blockchain networks, including Bitcoin. In PoW:

• Miners compete to solve complex mathematical puzzles
• The first miner to solve the puzzle gets to add the next block
• The puzzle involves finding a hash that starts with a certain number of zeros
• The difficulty of the puzzle is adjusted to maintain a consistent block time

PoW ensures that adding new blocks is computationally expensive, making it difficult and costly to attack or manipulate the blockchain.

A 51% attack is a potential threat to blockchain networks where an entity gains control of more than 50% of the network's mining power. This scenario:

• Allows the attacker to potentially reverse transactions
• Enables double-spending of coins
• Can prevent new transactions from gaining confirmations
• Might allow the attacker to exclude or modify the ordering of transactions

While theoretically possible, a 51% attack is extremely difficult and costly to execute on large, established blockchain networks. The attacker would need to invest in enormous computational power, and the attack's success could potentially devalue the very cryptocurrency they're attacking.

Blockchain networks implement various measures to prevent and mitigate the risk of 51% attacks, including: increasing the number of confirmations required for large transactions, implementing checkpoints to prevent deep reorganizations of the blockchain, and encouraging decentralization of mining power.