请用英语解释什么是区块链，并提供三个关键特点，每个特点单独一行。
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Blockchain is a decentralized digital ledger technology that records transactions across a network of computers, ensuring transparency and security.

Decentralization: Transactions are verified by multiple nodes, eliminating the need for a central authority.

Transparency: All network participants can view the transaction history, ensuring accountability.

Immutability: Once data is recorded, it cannot be altered, providing a secure and reliable record of transactions.
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