Add any data to Ethereum transaction
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
[Ping An Bank I know] want to know more? Come and see "Ping An Bank I know" ~
https://b.pingan.com.cn/paim/iknow/index.html
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
the concept of bitcoin was first proposed by Nakamoto on November 1, 2008, and was officially born on January 3, 2009 [1]. According to the idea of Nakamoto, the open source software is designed and released, and the P2P network on it is constructed. Bitcoin is a virtual encrypted digital currency in the form of P2P. Point to point transmission means a decentralized payment system
Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized Ethereum virtual machine to process point-to-point contract through its special cryptocurrency ether (ETH)
warm tips:
1. The above information is for reference only, without any suggestions
2. According to the notice on preventing the financing risk of token issuance, there is no approved digital currency trading platform in China. According to the regulation of digital currency in China, investors have the freedom to participate in digital currency transactions at their own risk
response time: February 1, 2021. Please refer to the official website of Ping An Bank for the latest business changes
[Ping An Bank I know] want to know more? Come and see "Ping An Bank I know" ~
https://b.pingan.com.cn/paim/iknow/index.html
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address
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
Transaction
the behavior of blockchain transaction follows different rule sets
< UL >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
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)
< / UL >
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system