A blockchain is a type of distributed ledger — a record-keeping system maintained across many computers rather than a single central database.
Key characteristics
- Records are grouped into "blocks" that are cryptographically linked in sequence.
- Once added, data is very difficult to alter without changing all subsequent blocks.
- Multiple network participants maintain copies of the ledger, rather than one central party.
- Consensus mechanisms determine how new blocks are validated and added.
Beyond cryptocurrency
While blockchain technology underpins cryptocurrencies, the same underlying concept has been explored for other applications, including supply chain tracking and digital identity — though adoption and maturity vary widely across use cases.



