Simply put, the four core technologies of blockchain are distributed ledger, consensus mechanism, cryptography, and smart contracts. They respectively serve the functions of data storage, data processing, data security, and data application in blockchain. Specifically, their relationship is as follows:

First, the distributed ledger forms the framework of blockchain. It is essentially a distributed database where data, once generated and processed by participants, is stored. Thus, the distributed ledger serves the role of data storage in blockchain.

Second, the decentralized nature of the distributed ledger means the blockchain network is a distributed structure where anyone can freely join and participate in data recording. However, this also leads to the notorious "Byzantine Generals Problem"—the more participants in the network, the harder it becomes to achieve consensus.

Therefore, another mechanism is needed to coordinate all nodes and maintain consistency in the ledger. The consensus mechanism establishes a set of rules to define how each participant processes data and achieves agreement among nodes by competing for the right to record transactions. The data processed by the winner of this competition is adopted by the entire network. Thus, the consensus mechanism plays the role of coordinating node behavior and clarifying data processing in blockchain.

Moreover, data entering the distributed database is not simply packaged and stored. The underlying data structure is determined by blockchain cryptography.

The packaged data blocks are processed into a chain structure through cryptographic hash functions, where each subsequent block contains the hash of the previous one. Due to the one-way and tamper-resistant nature of hash algorithms, once data is on the blockchain, it cannot be altered and remains traceable.

Additionally, your account is encrypted using asymmetric encryption, ensuring data security and verifying data ownership.

Finally, smart contracts can be built on top of the distributed ledger at the application level. When addressing trust issues, smart contracts allow agreements between users to be clearly defined in code, with conditions listed and executed by the program. Data on the blockchain can also be accessed through smart contracts. Thus, smart contracts serve the function of data execution and application in blockchain.

In summary, the four core technologies each play their own role in blockchain, collectively building its foundation. We are fortunate to be part of this era, riding the wave of blockchain technology.