What Is a Blockchain?
The blockchain is a public ledger of every Bitcoin transaction ever made. It's essentially a digital record book, shared and validated by a global network of computers, ensuring that it remains secure and transparent.
A Digital Ledger
Think of it as a giant, shared spreadsheet. Each new entry is a transaction, and the entire history is available for anyone to see. This transparency is a core feature of Bitcoin.
A Chain of Blocks
Transactions are grouped into blocks, and each block is cryptographically linked to the one before it. This forms an unbroken, chronological chain, hence the name "blockchain."
Decentralized and Distributed
No single person or company owns the blockchain. Instead, a copy is held by thousands of participants (nodes) worldwide. This decentralization makes it incredibly resilient and censorship-resistant.
Immutable and Secure
Because each block is linked to the previous one, changing a past transaction is practically impossible. Any alteration would require immense computational power to redo all subsequent blocks, a feat that is considered unfeasible. This makes the blockchain an immutable and highly secure record of ownership.