Which concept uses a chain of blocks to securely record transactions and maintain integrity through cryptography?

Which concept uses a chain of blocks to securely record transactions and maintain integrity through cryptography?

• A. Blockchain
• B. Open public ledger
• C. Merkle Tree
• D. Hash Chain

Answer: (B)

The key idea here is blockchain technology. It stores transactions in blocks that are linked together through cryptographic hashes. Each block contains a list of transactions and a hash that points to the previous block, creating a chain back to the first block. This chain of blocks secured by cryptography makes it extremely hard to alter past records—incidentally, changing one block would require recalculating hashes for all following blocks, and in a distributed system that would mean obtaining control of a majority of the network’s computing power. An open public ledger describes a property you often see with blockchains—the ledger is transparent and accessible to participants—but the mechanism that guarantees integrity is the chaining of blocks with cryptographic links, not merely the idea of a shared ledger. A Merkle Tree, while important in block validation because it lets you verify that a specific transaction is included in a block without inspecting every transaction, is about verifying content inside a block rather than how blocks are linked. A Hash Chain, on the other hand, reflects a sequence secured by hashing but lacks the block structure and the distributed consensus that give blockchain its distinct properties. So the concept being described is blockchain.

The key idea here is blockchain technology. It stores transactions in blocks that are linked together through cryptographic hashes. Each block contains a list of transactions and a hash that points to the previous block, creating a chain back to the first block. This chain of blocks secured by cryptography makes it extremely hard to alter past records—incidentally, changing one block would require recalculating hashes for all following blocks, and in a distributed system that would mean obtaining control of a majority of the network’s computing power.

An open public ledger describes a property you often see with blockchains—the ledger is transparent and accessible to participants—but the mechanism that guarantees integrity is the chaining of blocks with cryptographic links, not merely the idea of a shared ledger. A Merkle Tree, while important in block validation because it lets you verify that a specific transaction is included in a block without inspecting every transaction, is about verifying content inside a block rather than how blocks are linked. A Hash Chain, on the other hand, reflects a sequence secured by hashing but lacks the block structure and the distributed consensus that give blockchain its distinct properties.

So the concept being described is blockchain.