Blockchain is a distributed ledger technology that records transactions across a network of computers without relying on a central authority. Each block contains a batch of transactions, a timestamp, and a cryptographic hash linking it to the previous block.
Decentralization is the core principle behind blockchain — no single entity controls the network. Instead, participants collectively validate and agree on the state of the ledger through consensus mechanisms like Proof of Work or Proof of Stake.
Understanding these concepts is essential for anyone working with cryptocurrency, smart contracts, or decentralized applications. The building blocks — hashing, Merkle trees, and consensus — appear across many areas of modern technology.