Shared blockchain data storage learning

Shared blockchain data storage learning

Term definitionBlockchainA distributed database that records transaction data in a secure and immutable way. BlockThe basic unit of the blockchain, containing a set of verified transaction data. Consensus nodeA node that participates in the consensus process of the blockchain network and is responsible for verifying and adding blocks. Merkle treeA data structure used to efficiently verify transaction data in a block. Merkle root hashThe hash value of the root node of the Merkle tree, representing the hash value of all data in the entire tree. State dataData that reflects the current state of the blockchain network, such as account balances. The historical state tree stores the tree structure of all historical state data of the blockchain network. The current state tree stores the tree structure of the current block state data. Shared storage nodesStore special nodes of the historical state tree, which other nodes can access to obtain historical state data. Key value pair (KVP)A data storage method that uses a key to access the corresponding value. Byzantine fault tolerance (BFT)A consensus mechanism that tolerates malicious or faulty nodes in the system. Practical Byzantine fault tolerance (PBFT)An efficient Byzantine fault tolerant consensus mechanism suitable for scenarios such as consortium chains. Proof of Authority (POA)A consensus mechanism that relies on pre-selected authoritative nodes to verify and add blocks. Fixed Depth Merkle Tree (FDMT)An improved Merkle tree structure that can store and access state data more efficiently. Cloud StorageAn Internet-based storage service that provides large-capacity, scalable storage space.

Short Answer Questions

Briefly describe the basic concepts of blockchain and how it works. Blockchain is a decentralized distributed ledger technology used to record and verify transaction data. It works by packaging transaction data into blocks, each of which contains the hash value of the previous block to form a chain structure. The consensus mechanism is used to ensure that all nodes agree on the blockchain data.

Explain the role of Merkle tree in blockchain. Merkle tree is used to efficiently verify transaction data in a block. It pairs the hash values ​​of all transaction data for hashing operations, and finally obtains a root hash value, namely the Merkle root hash. By comparing the Merkle root hash, the integrity of the block data can be quickly verified.

What is the main difference between consortium chain and public chain? A consortium chain is a semi-closed blockchain network that requires authorization to join. It is suitable for scenarios such as inter-enterprise collaboration. A public chain is a completely open network that anyone can join and participate in, such as Bitcoin and Ethereum.

How does the PBFT consensus mechanism work? PBFT is a consensus mechanism based on message passing that ensures that all nodes agree on the order of transactions through multiple rounds of voting. Even if there are malicious nodes, as long as their number does not exceed one-third, PBFT can still ensure the normal operation of the system.

Why is it necessary to introduce shared storage nodes in the blockchain network? As the blockchain network continues to grow, the historical state data will become larger and larger, and storing this data will consume a lot of storage resources. Introducing shared storage nodes can store historical state data on dedicated nodes, reduce the storage burden of other nodes, and improve the overall efficiency of the network.

Explain the difference between the historical state tree and the current state tree. The historical state tree stores all the historical state data of the blockchain network, while the current state tree only stores the state data of the current block. The current state tree is much smaller than the historical state tree, so it can be accessed and updated more efficiently.

What is a fixed-depth Merkle tree (FDMT) and how is it different from a traditional Merkle tree? FDMT is an improved Merkle tree structure that stores state data in a tree of fixed depth, which can be updated and accessed more efficiently. Compared with the traditional Merkle tree, FDMT is more space-saving and easier to implement.

How does a shared storage node verify the validity of the received state data? A shared storage node can verify its validity by calculating the hash value of the received state data and comparing it with the state root hash in the blockchain. If the hash values ​​match, the state data is valid.

How does a consensus node obtain historical state data from a shared storage node? A consensus node can obtain historical state data by sending the corresponding hash value to a shared storage node. The shared storage node will find the corresponding state data based on the hash value and return it to the consensus node.

Briefly describe the application scenarios of cloud storage in blockchain. Cloud storage can provide blockchain networks with large-capacity, scalable storage space for storing historical state data, block data, etc. Cloud storage can also improve the availability and reliability of data and reduce storage costs.

Answers to short-answer questions

Blockchain is a distributed database that maintains a growing list of records, called blocks. Each block contains the hash value of the previous block, forming a chain structure. This structure makes it difficult to tamper with the data on the blockchain, because any change to the data will change the hash value of subsequent blocks. The blockchain uses a consensus mechanism to ensure that all nodes agree on the blockchain data.

The Merkle tree is used to efficiently verify the transaction data in the block. It performs hash operations by pairing the hash values ​​of all transactions in pairs, and finally obtains a root hash value, the Merkle root hash. This root hash value is stored in the block header. When it is necessary to verify whether a transaction exists in the block, only a small amount of hash operations are required along the path of the Merkle tree to verify whether the hash value of the transaction exists in the Merkle tree, thereby determining whether the transaction exists in the block.

The main difference between consortium chains and public chains lies in the permissions of participants and the openness of the network. A consortium chain is a blockchain network that requires authorization to join, and participants are usually institutions or individuals with specific identities. The public chain is a completely open blockchain network that anyone can join and participate freely.

The PBFT consensus mechanism is a consensus mechanism based on message passing, which ensures that all nodes agree on the order of transactions through multiple rounds of voting. The workflow of PBFT can be divided into three stages: pre-preparation stage, preparation stage, and submission stage. In the pre-preparation stage, the master node broadcasts the transaction to be processed to other nodes. In the preparation stage, other nodes verify the transaction and return the verification results to the master node. In the submission stage, after the master node collects enough verification results, it submits the transaction to the blockchain.

As the blockchain network continues to grow, the historical state data will become larger and larger, and storing this data will consume a lot of storage resources. The introduction of shared storage nodes can store historical state data on dedicated nodes, reduce the storage burden of other nodes, and improve the overall efficiency of the network.

The historical state tree stores all historical state data of the blockchain network, while the current state tree only stores the state data of the current block. The scale of the current state tree is much smaller than that of the historical state tree, so it can be accessed and updated more efficiently.

The fixed-depth Merkle tree (FDMT) is an improved Merkle tree structure that stores state data in a tree of fixed depth, which can be updated and accessed more efficiently. Compared with the traditional Merkle tree, FDMT is more space-saving and easier to implement.

The shared storage node can verify the validity of the received state data by calculating the hash value and comparing it with the state root hash in the blockchain. If the hash values ​​match, the state data is valid.

The consensus node can obtain historical state data by sending the corresponding hash value to the shared storage node. The shared storage node will find the corresponding state data based on the hash value and return it to the consensus node.

Cloud storage can provide large-capacity, scalable storage space for blockchain networks to store historical state data, block data, etc. Cloud storage can also improve data availability and reliability and reduce storage costs.