The Ethereum block records the state
what is Ethereum:
Ethereum is an innovation based on the application of technologies and concepts in bitcoin to computers. Ethereum itself imitates a lot of bitcoin technology to maintain the computer platform. blockchain technology is one of them
Ethereum platform can safely run any program users want
advantages of Ethereum over other competitive currencies before Ethereum appeared, some digital currencies imitated bitcoin. However, these projects have their own shortcomings, they can only support one or several specific applications at the same time< However, the reason why Ethereum can surpass the limitations of these projects in the past is because of the core idea of Ethereum
what Ethereum wants to implement is a blockchain protocol with built-in programming language. Since it supports programming language, in theory, any blockchain application can be defined with this language, and then run on Ethereum's blockchain protocol as an application
The design of Ethereum is very flexible and adaptable
Ethereum target sets the advantages of blockchain technology, in order to add the advantages of blockchain, such as decentralization, openness and security, to almost all computing fields
blockchain applications of Ethereum
Ethereum has many blockchain applications, such as digital applications of gold and stocks, financial derivatives applications, DNS and digital authentication, etc
Ethereum has achieved more than 100 blockchain applications by many start-ups
Ethereum has also been closely watched by some financial institutions, banking consortia (such as R3), as well as large companies like Samsung, Deloitte, RWE and IBM. As a result, a number of blockchain applications such as simplified and automated financial transactions, merchant loyalty index tracking, and gift cards designed to achieve decentralization of electronic transactions have emerged
the relationship between Ethereum and blockchain:
Ethereum is a programmable blockchain
Ethereum does not give users a series of preset operations (such as bitcoin transaction), but allows users to create complex operations according to their own wishes
in this way, Ethereum can be used as a platform for various types of decentralized blockchain applications, including but not limited to cryptocurrency
like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"
If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records
the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:
< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />}); Pre >
Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query
recommend a practical introction, you can see: Ethereum tutorial
you can't retrieve your assets through Ethereum block query
think too much
if you want to check the real estate,
you can go to the real estate transaction registration center.
in today's mobile payment era, few people will use coins for payment . A lot of people, they think that mobile payment is more convenient, if you carry RMB, it will be very troublesome, so now less and less people use paper money to pay. In fact, the process of making paper money is also very complicated. The materials used to make coins are different metals. Compared with those rare metals, low-cost metals are more suitable for making coins
< / blockquote >and those rare metals, such as gold or silver, are suitable for making commemorative coins with collection value . In many countries, some of their currencies are made of alloy, because it is a very ideal material for coinage, and the hardness is improved by mixing with other metals. At the beginning of making coins, we should choose the materials and put the selected metals in the furnace for casting and melting. After many times of rolling in the rolling workshop, the thickness of the coin can meet the requirements of coins, and it can be made into semi-finished procts for further processing{ RRRRR}
with the progress of science and technology, now many mold making machines have become engraving machines for casting to replace the previous manual process . It can improve the accuracy to a certain extent. It used to take a whole day to manufacture, but now it can complete the remanufacturing of the mold within a few hours. After that, it can be pressed on the coin, and the coin will become the currency in circulation
Characteristics of blockchain
one of the four characteristics of blockchain: tamper proof
the most easily understood characteristic of blockchain is tamper proof
tamper proof is based on the unique account book of "block + Chain": the blocks with transactions are added to the end of the chain in time order. To modify the data in a block, you need to regenerate all blocks after it
one of the important roles of consensus mechanism is to make it almost impossible to modify a large number of blocks at high cost. Take the blockchain network (such as bitcoin and Ethereum) with workload proof as an example, only with 51% of computing power can all blocks be regenerated to tamper with data. However, the destruction of data is not in line with the self-interest of players with large computing power. This practical design enhances the reliability of data on the blockchain
generally, the transaction data in the blockchain ledger can not be "modified", it can only be "modified" through the new transactions that are approved. The process of correction will leave traces, which is why the blockchain can not be tampered with. Tampering refers to changing or misinterpreting by means of forgery
in today's common files and relational data, unless a special design is adopted, the system itself does not record modification traces. Blockchain ledger adopts a design different from that of files and databases. It draws on the design of ledger in reality, that is, to retain the traces of records. Therefore, we can not "modify" the account book without leaving traces, but can only "modify" the account book (see Figure 2)
Figure 6: bitcoin is centralized in the organization and logically centralized
when we imagine the future organization, the ideal prototype in our mind is often bitcoin organization: completely decentralized autonomous organization. But in practice, for the sake of efficiency and advancement, we will move closer to the centralized organization and finally find a suitable balance point
nowadays, in the blockchain projects that are created and issued through the smart contract of Ethereum and run in a community or ecological way, the ideal state of many projects is similar to the bitcoin organization, but the actual situation is between the completely decentralized organization and the traditional company
when we discuss the fourth feature of blockchain, which is decentralized self-organization, we are actually going out of the code world, involving human organization and collaboration. Now, various discussions and practical explorations have also revealed the significance of blockchain beyond technology: it may serve as an infrastructure to support human proction organization and collaborative change. This is another example of the complete isomorphism between blockchain and Internet. Internet is not only a technology, it has changed people's organization and collaboration
in general, Ethereum has brought blockchain into a new stage. When discussing Ethereum, if we want to summarize two key words, they are smart contract and token; If I can only say one, I will choose "Tong Zheng". I would rather look for its meaning from the history of the Internet and repeat the previous analogy: as a token of value, its role is similar to HTML. With HTML, what kind of website to build depends entirely on our imagination
eth. M is characterized by providing a complete intelligent business blockchain architecture for enterprise users and government partners on the Bi platform, providing users with a perfect data import scheme and a variety of classic distributed computing models, which can more quickly solve users' massive data computing problems and effectively rece enterprise costs, And create a new business model on the basis of data security. Blockchain is a new field that needs to be combined with market demand. We can solve some pain points in the instry in data storage security, data retrieval and data filtering. For blockchain framework, business model and technology, we focus on building mature blockchain procts with the most appropriate and proven technology
blockchain, originally just a settlement system of bitcoin, is essentially a decentralized accounting scheme based on cryptography. The technology used by blockchain itself is not a new concept, but a collection of cryptography technologies. Through ingenious design, it realizes the demand of decentralized settlement. However, it is accompanied by some derivative problems. Users are used to transferring and sharing information in the distributed storage space, namely Internet. However, if we want to complete the transfer of money value, we are used to using centralized and trusted third-party transaction intermediaries, such as banks. Although online payment is becoming more and more popular, bank card and password are still needed to register online payment account. The use of blockchain transactions is decentralized and does not require a third-party intermediary. Blockchain realizes the following three important functions: recording transaction information, verifying identity and establishing contract. It's going to be a big change. Because around the world, financial services are the largest sector in terms of market value. Even if it replaces a small part of business, blockchain can have a huge impact on the traditional financial field. At the same time, eth. M blockchain will also improve the efficiency of data management in the whole field. The function of establishing contracts will make the value of blockchain not limited to the financial field. This is the core of eth. M. blockchain can be used to store any information, even software code. That is to say, it can be realized by programming. When the relevant parties provide the relevant key, the transaction can be executed. The same program can also be used to obtain external data: stock index data, weather, news headlines or other data that can be analyzed by computer. In this way, the pre verified contract can be executed automatically when the specified conditions are met. Contracts executed on the blockchain are called "smart contracts"
in the future, eth. M's smart contract application scenarios are very wide, for example:
1. In the field of electric power, if the smart temperature regulator is used to collect the power utilization status of the smart grid in real time, when the wattage consumed by a certain company is monitored to reach a certain amount, the company account and the electric power company's transfer will be completed, and the automatic payment will be realized
2. In the medical field, if a doctor / patient stores the data of blood glucose meter in the form of blockchain, then the patient's physical sign data can be completely and accurately recorded. Blood glucose data can trigger insulin controller to help patients control blood glucose in a safe range
3. In the field of intellectual property supervision, blockchain can be used to monitor the number of times users use, share and a protected proct.