Ethereum changes synchronization data

1. Eth is a kind of digital token of Ethereum, which is regarded as "bitcoin version 2.0". It adopts the blockchain technology "Ethereum", which is different from bitcoin. It is an open-source public blockchain platform with intelligent contract results, and a resonance network composed of tens of thousands of computers around the world. Developers need to pay eth to support the application. Like other digital currencies, ether currency can be bought and sold on the trading platform

warm tips: the above explanations are for reference only, without any suggestions. There are risks in entering the market, so investment should be cautious. Before making any investment, you should make sure that you fully understand the nature of the investment and the risks involved in the proct. After a detailed understanding and careful evaluation of the proct, you can judge whether to participate in the transaction
response time: December 2, 2020. Please refer to the official website of Ping An Bank for the latest business changes
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2. A virtual currency with a wallet doesn't mean it's more professional and advanced. The existence of digital currency wallet is the premise of currency existence. Currency without wallet can be identified as fraud
mainstream digital currencies such as bitcoin, Puyin, Laite, Ethereum and dogcoin all exist in wallets, and wallets existed before the release of such currencies.

3.

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

4. Through curl to simulate, and then get the data, and use it in JSON format

5. Ethereum is not a scam, but there are countless scams designed by criminals around Ethereum. The best way to avoid Ethereum scams is not to trust the guaranteed return on investment and manage your own money bag. Choose a formal digital currency exchange to invest. At present, the mainstream digital currency transactions in the market are all coin security, fire coin network, bitnet, etc.

6. The bifurcation of Ethereum Constantinople is about to begin. Many people are curious about this bifurcation and are not sure whether they need to be prepared in advance
to put it simply: if you are only the holder of eth, you don't need to make any preparation for this upgrade.

7. You can use Tencent mobile housekeeper backup,
1. Go to the home page of Tencent mobile housekeeper, click the "Settings" button,

2. Click to enter the "utility" page, find the "synchronization assistant" tool, and if not installed, add the synchronization assistant in the "add tool"

3. Enter the synchronization assistant, and click the update button to synchronize the mobile information

4 Finally, click the "OK" button to complete the synchronization

5. If the mobile phone information is lost, you can retrieve the corresponding information in "my device" - "my mobile phone" by logging in QQ and restore it to the mobile phone.

8. Blockchain technology has a natural advantage in the realization of smart contracts
bitcoin, Ruitai coin, Laite coin, Ethereum and other digital cryptocurrencies all use blockchain technology
blockchain is an important concept of bitcoin, which is essentially a decentralized database. At the same time, as the underlying technology of bitcoin, it is used to verify the validity of its information (anti-counterfeiting) and generate the next block. Blockchain is a series of data blocks generated by cryptography, each of which contains the information of a bitcoin network transaction

9. Swarm is a distributed storage platform and content distribution service, and a local service layer of Ethereum Web3 stack. The main goal of swarm is to provide enough decentralized and repetitive storage for Ethereum public records, especially DAPP code and data and block data. From an economic point of view, it will encourage some participants to concentrate their storage and bandwidth resources to provide the above services for other network members.

10.

Transaction

the behavior of blockchain transaction follows different rule sets

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e to the distributed and unlicensed nature of public blockchain, anyone can sign the transaction and broadcast it to the network

according to different blockchains, traders will be charged a certain transaction fee, which depends on the needs of users rather than the value of assets in the transaction

blockchain transactions do not require any central authority verification. It only needs to use the digital signature algorithm (DSA) corresponding to its blockchain to sign it with the private key

once a transaction is signed, broadcast to the network and mined into a successful block in the network, the transaction cannot be recovered

Ethereum transaction structure

Ethereum transaction data structure: transaction 0.1 eth

{
& 39; nonce':&# 39; 0x00', // Decimal: 0
& 39; gasLimit': &# 39; 0x5208', // Decimal system: 21000
& 39; gasPrice': &# 39; 0x3b9aca00', // Decimal system: 10000000000
& 39; to': &# 39;&# 39; ，// Sending address
& 39; value': &# 39; 0x16345785d8a0000',// 100000000000000000 ，10^17
' data': &# 39; 0x', // Decimal representation of null data; chainId': 1 / / blockchain network ID
}

these data have nothing to do with the transaction content, but have something to do with the execution mode of the transaction. This is because when you send a transaction in Ethereum, you must define some other parameters to tell miners how to handle your transaction. Transaction data structure has two attribute designs & quot; gas": & quot; gasPrice",& quot; gasLimit"

" gasPrice": The unit is Gwei, which is 1 / 1000 eth, indicating the transaction cost

& quot; gasLimit": The maximum gas charge allowed for the transaction

these two values are usually filled in automatically by the wallet provider

in addition, you need to specify which Ethereum network to execute the transaction (chainid): 1 represents the Ethereum main network

ring development, tests are usually carried out locally and on the test network, and transactions are carried out through the test eth issued by the test network to avoid economic losses. After the test, enter the main network transaction

in addition, if you need to submit some other data, you can use & quot; data" And & quot; nonce" Attach as part of a transaction

a nonce (number used only once) is the value used by Ethereum to track transactions, which helps to avoid double spending and replay attacks in the network

Ethereum transaction signature

Ethereum transaction involves ECDSA algorithm. Taking JavaScript code as an example, the popular ethers.js is used to call ECDSA algorithm for transaction signature

const ethers = require(' ethers')

const signer = new ethers.Wallet(' Wallet address

signer.signTransaction({

' nonce':&# 39; 0x00', // Decimal: 0

& 39; gasLimit': &# 39; 0x5208', // Decimal: 21000

& 39; gasPrice': &# 39; 0x3b9aca00', // Decimal 10000000000

& 39; to': &# 39;&# 39; ，// Sending address

& 39; value': &# 39; 0x16345785d8a0000',// 100000000000000000 ，10^17

' data': &# 39; 0x', // Decimal representation of null data

& 39; chainId': 1 / / blockchain network ID

})

. Then (console. Log)

you can use the online application composer to deliver signed transactions to Ethereum. This is known as "offline signature.". Offline signatures are particularly useful for applications such as status channels, which are smart contracts that track the balance between two accounts and transfer funds after a signed transaction is submitted. Offline signature is also a common practice in dexes

you can also use online wallet to create signature verification and broadcast through Ethereum account

with Portis, you can sign a transaction to interact with the gas station network (GSN)

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