Marcin Frąckiewicz

Blockchain is a decentralized, distributed digital ledger that securely records transactions across a network of computers without a central authority geeksforgeeks.org. At its core, a blockchain consists of a chain of data blocks linked together using cryptography; each block contains a bundle of transactions and a hash referencing the previous block, forming an immutable chain geeksforgeeks.org geeksforgeeks.org. This design ensures that once a block is added, its data cannot be altered without changing all subsequent blocks, providing immutability and tamper-resistance. Transactions are validated by network nodes and grouped into blocks, which are then confirmed by achieving distributed consensus – an agreement among the network on the block’s validity geeksforgeeks.org. Common consensus mechanisms include Proof of Work, where nodes solve complex puzzles, and Proof of Stake, where validators “stake” tokens for the right to add new blocks geeksforgeeks.org. This consensus-driven validation, combined with cryptographic security, allows blockchains to replace the need for a trusted third-party with mathematical proof and distributed agreement on “truth” cryptoaltruism.org brainyquote.com.