💻Blockchain and data structure

Blockchain technology, as a decentralized dis- tributed data storage and management system, is centered on its unique data structure design. The blockchain data structure achieves security, in- tegrity and tamper-evident data through cryptogra- phy and distributed consensus algorithms. Merkle Tree (MT) [7] is a common data structure for stor- ing part of blockchain data. MT is a binary tree structure whose leaf nodes store the hash of data and non-leaf nodes store the hash of their children’s hash.The main role of MT is to provide data in- tegrity verification and fast data retrieval. When the number of data blocks is large, by verifying the hash value of the root node it is possible to deter- mine whether all data blocks have been tampered with. In addition, due to the uniqueness and irre- versibility of the hash value, the hash value of any data block can be found or a data block can be veri- fied quickly by Merkle tree. This structure ensures data integrity and consistency, while improving the efficiency of data validation and query.

In practical applications, blockchains often need to handle large amounts of off-chain data. In order to ensure the security and integrity of off-chain data, blockchain networks can adopt on- chain verification technology for off-chain data. This technique achieves effective verification of off- chain data by storing the hash value or Merkle tree root node [7] of off-chain data on the blockchain. This approach reduces the storage pressure of the blockchain network and ensures the security and integrity of the off-chain data.

Blockchain is closely related to data struc- ture. Through technologies such as Merkle state machine, block composition, and off-chain data on- chain checksum, blockchain technology achieves data security, integrity, and tamper-evident, pro- viding a reliable data foundation for various appli- cation scenarios. The following subsections will introduce the relationship between blockchain and data structure in details, including Merkle state machine, block composition, and off-chain data on-chain checksum.