Blockchain
Protocol
Append-only ledger of blocks secured by cryptography.
A blockchain is a shared database that anyone can verify. Transactions are grouped into blocks and linked together with hashes. Consensus rules and incentives keep participants honest without a single trusted party. Developers use blockchains for payments, assets, and apps that need open access and auditability.
Frequently asked questions
Why is a blockchain hard to tamper with?
Each block links to the previous one with a hash. Changing history would require redoing work or stake, which is costly.What can run on a blockchain?
Payments, tokens, smart contracts, and applications that need shared state or trust minimization.How do different blockchains vary?
They trade off performance, security, and decentralization. Some focus on smart contracts, others on payments or data availability.