Which statement is NOT a key feature of blockchain?

Which statement is NOT a key feature of blockchain?

• A. Centralized
• B. Decentralized
• C. Verifiable
• D. Immutable

Answer: (A)

Blockchain is built as a decentralized, verifiable, and immutable distributed ledger; centralization is not a feature. The network runs across many nodes that each hold copies of the ledger and reach agreement through a consensus mechanism, so no single party controls the data. This decentralization provides resilience and reduces the need to trust one entity. Verifiability comes from cryptographic proofs: transactions are signed, blocks contain hash links to previous blocks, and anyone can independently verify the chain's integrity. Immutability arises because altering a past block would require recomputing proofs across the network, making retroactive changes practically infeasible. While some systems may include centralized components in practice, the core blockchain design centers on decentralization, verifiability, and immutability, not centralization.

Blockchain is built as a decentralized, verifiable, and immutable distributed ledger; centralization is not a feature. The network runs across many nodes that each hold copies of the ledger and reach agreement through a consensus mechanism, so no single party controls the data. This decentralization provides resilience and reduces the need to trust one entity. Verifiability comes from cryptographic proofs: transactions are signed, blocks contain hash links to previous blocks, and anyone can independently verify the chain's integrity. Immutability arises because altering a past block would require recomputing proofs across the network, making retroactive changes practically infeasible. While some systems may include centralized components in practice, the core blockchain design centers on decentralization, verifiability, and immutability, not centralization.