Literature reading: [1] Hua Yazhou. Research on spatiotemporal data storage and query methods based on improved Block-DAG blockchain [D]. Liaoning University, 2022. DOI: 10.27209/d.cnki.glniu.2022.001364. [1] Hua Asia, Ding Linlin, Chen Ze, et al. Blockchain construction and query method for spatiotemporal data [J]. Computer Applications, 2022, 42(11): 3429-3437.
Literature summary:
question:
- Traditional blockchain? accomplish?
- Sidechain technology?
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Blockchain 1. 0 represented by Bitcoin , Blockchain 2. 0 represented by Ethereum, and Blockchain 3. 0 represented by the DAG structure? the difference?
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Off-topic knowledge
DAPP
(1) What is DAPP?
DAPP is the abbreviation of Decentralized Application, which is decentralized application, and some people call it distributed application . It is considered to have opened the blockchain 3.0 era .
DAPP is a variety of distributed applications derived from the underlying blockchain platform, and is a form of service provision in the blockchain world. DAPP is to the blockchain, somewhat like APP is to IOS and Android.
(2) The relationship between DAPP, smart contracts and blockchain
It can be considered that DAPP is a distributed application running on smart contracts based on P2P peer-to-peer network , and the blockchain provides trusted data records for it.
(3) About smart contracts
Smart contracts are a concept that appeared before the Bitcoin era and was first proposed by Nick Szabo in 1996. His definition of smart contracts is as follows:
“A smart contract is a set of agreements defined in digital form, including protocols on which contract participants can execute these agreements. The basic idea of smart contracts is that a variety of contract terms can be embedded into the hardware and software we use This makes it very costly for the attacker to attack."
The construction and execution of smart contracts based on blockchain are divided into the following steps: 1. Multiple users jointly participate in formulating a smart contract; 2. The contract is diffused through the P2P network and stored in the blockchain; 3. The intelligence built by the blockchain The contract executes automatically.
(4) Characteristics of DAPP
At present, there is no unified view on the characteristics of DAPP, but they are basically the same. Here we try to summarize them as follows.
1. DApp operates decentralized through network nodes. It can run on the user's personal devices, such as mobile phones and personal computers. It belongs to the user forever and can be freely transferred to anyone.
2. DApp runs on a peer-to-peer network. It does not rely on a central server, does not require a dedicated communication server to transmit messages, and does not require a central database to record data. Data is saved in the user's personal space, which may be a mobile phone or a personal cloud disk.
3. DApp data is encrypted and stored on the blockchain. Property rights transactions and sales can be carried out relying on the blockchain, carrying transaction methods without intermediaries.
4. DApp participant information is stored securely. It can protect digital assets and ensure that property rights will not be leaked or destroyed.
5. DApp must be open source and autonomous. It can be freely packaged and generated by users, and signatures mark ownership. Its distribution is not subject to any institutional restrictions. All kinds of creativity and innovation can be freely expressed and realized.