Ethereum block traversal
a brief history of etheric Classics (etc)
etheric classics began with an unfortunate event
in May 2016, the decentralized autonomous organization (DAO) held a token sale with the goal of establishing a blockchain based venture capital to fund future decentralized applications (dapps) in the Ethereum ecosystem
basically, Dao is a complex smart contract that operates in a decentralized way - computer code that automatically performs tasks between multiple parties when conditions are met
despite its ambitious goals and successful token sales, Dao's code has a major vulnerability that allows attackers to steal eth from decentralized organizations
the attacker took advantage of this vulnerability in June 2016, triggering the infamous Dao hacking event, and maliciously stole eth worth about US $50 million
there is no doubt that Dao hacking has shocked Ethereum community and made eth price drop from $20 to $13
after the Dao hacking, the Ethereum community has to choose from three options
< UL >do nothing and try to bear the consequences of the attack
start soft bifurcation to recover funds
deploy a hard fork to recover the lost eth
both soft and hard bifurcations are significant network upgrades. However, soft fork allows users who are not upgraded to communicate with upgraded users, while hard fork is not backward compatible with previous versions
as developers realize that deploying soft forks will expose the network to distributed denial of service (DDoS) attacks, Ethereum community decides to initiate hard forks to recover the funds lost in Dao hacking attacks
although this scheme is supported by most people, a small number of people in Ethereum community oppose it. They think that "code is the law" and blockchain network should be unchangeable
the failure of both sides to reach an agreement on the solution eventually led to the fragmentation of Ethereum blockchain
those who tried to recover the lost eth chose the hard fork and opened the Ethereum (ETH) blockchain as we know it today, while another group stayed on the original Ethereum classic (etc) chain
what problems does ethereal classic solve Ethernet classic (etc) is a blockchain platform that allows developers to deploy smart contracts and dapps although this function is the same as Ethereum (ETH), etc blockchain has two main differences first of all, Ethereum classic community opposes tampering with distributed ledger and supports the view that "blockchain network cannot and should not be modified" secondly, although there is no rigid upper limit on the total supply of eth, it is allowed to create 230 million etc at most by adopting the monetary policy of constant supply as a bonus item, ethereal classic launched Atlantis hard bifurcation last year to increase the interaction with Ethereum and improve the privacy protection of transactions through ZK snarks the trading platforms recommended by ethereal classic etc are: Fire coin, okex, AAX, etc
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"
At present, the mining mode can be roughly divided into PPLNs, PPS and PPS +. However, if you want to get a stable income from mining, it is recommended to choose the mining software of PPS mode
when miners are mining, if you want to know how many etheric coins you get, you can use ha Yu miner to see clearly the daily mining income
Harbin miners showed a unified display of revenue for BTC, easy to see, and support for cash withdrawals to Alipay wallet and bitcoin wallet. p>
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 />});
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