What is the essence of blockchain technology?

The essence of blockchain technology lies in its foundational structure, which consists of a growing list of records, or blocks, that are linked together using cryptographic principles. This design ensures that each block is securely connected to the previous one, forming an immutable chain of data. The use of cryptography not only safeguards the integrity of the data but also enhances privacy and security, ensuring that once information is recorded on the blockchain, it cannot be altered or deleted without consensus from the network.

This unique architecture allows for decentralized trust, meaning that no single entity has control over the entire chain, which distinguishes blockchain from traditional centralized databases. Each participant in the network can verify and audit the records without needing a central authority, promoting transparency and accountability.

In contrast, the other options focus on different aspects that do not capture the full essence of blockchain technology. While coded applications for data privacy and user access protocols are significant in the context of data security, they do not represent the core principle of blockchain itself, which is centered around a transparent and tamper-proof record-keeping system. Similarly, a centralized ledger contradicts the decentralized nature that blockchain embodies. Thus, option B accurately encapsulates the fundamental characteristic of blockchain technology.