Which of the following statements about blockchain is NOT true?

The statement that it has a centralized validation system is not true because blockchain technology is fundamentally designed as a decentralized system. In a blockchain, transactions and data are validated through a network of nodes or participants, rather than a single central authority. This decentralization enhances security, transparency, and trust among participants, as it prevents any single entity from having complete control over the data.

In contrast, the other statements are true: blockchain is indeed a distributed ledger that records transactions, it utilizes cryptographic methods to secure transaction records, and it serves as the underlying technology for Bitcoin, facilitating the peer-to-peer currency transactions without the need for intermediaries. This decentralized validation process distinguishes blockchain from traditional centralized systems, and understanding this is key to grasping how blockchain operates effectively in various applications.