Ethereum geth create account

2. To create a Genesis configuration file:
first, you need to create a "Genesis" JSON configuration file, which describes some parameters of the genesis block. The following is the content of the file:
{
& quot; coinbase": & quot;& quot;,< br />" config": {< br />" homesteadBlock": 5
},
" difficulty": & quot; 0x20000",< br />" extraData": & quot; 0x",< br />" gasLimit": & quot; 0x2FEFD8",< br />" mixhash": & quot;& quot;,< br />" nonce": & quot; 0x0",< br />" parentHash": & quot; 000000000000000000000000",< br />" timestamp": & quot; 0x00",< br />" alloc": {< br />"& quot;:< br />{
" balance":& quot;& quot;
}
}
} 1234567891011213141516171819

the above code into a text file and name it genesis.json

Genesis!:
in order not to conflict with the data of the main chain, it is recommended to establish your own private chain data folder. On my computer, I built an ethdbspace as the Ethereum experimental work area on disk e, and created a privchain folder as the data storage folder of my first private chain
here, in order to facilitate management, I put genesis.json under the ethdbspace folder
open the windows command line

type the following command
geth -- dataDir & quot; E:\ EthDBSpace\ PrivChain" init " E:\ EthDBSpace\ genesis.json" 1

– the dataDir option is used to specify the data directory of our private chain. On my computer, it's E: &; EthDBSpace\ Privchain
init is the genesis command, followed by our Genesis configuration file path
after clicking enter, the execution result is as follows

at this time, genesis is complete
create an account:
in order to do experiments on the private chain, we also need to create our own account on the private chain
windows command line, type
geth -- dataDir & quot; E:\ EthDBSpace\ PrivChain" Console1

we have successfully created the world, so when we enter the client for the second time, we do not need to specify the genesis.json file path again, but directly – dataDir to indicate the private link data path
the console command is used to open the command line of geth
after clicking enter, the client will be initialized for a while. After the command prompt appears, it means that you have entered the geth console

type
personal. Newaccount (& #) in the geth command line; Your Password') 1

the personal.newaccount function is used to create an account, in which the parameter is the account password.
after clicking enter, the account creation address will be listed in green below the command, that is, the public key of the account.
we can check the account balance first, In the geth command line, type:
My = eth. Accounts [0]
eth. Getbalance (my) 12

My = eth. Accounts [0]. The purpose of this sentence is to assign the account address we just created to my variable. This can simplify the subsequent account address input. Among them, eth.accounts records the addresses of all accounts on this machine. Since we created an account for the first time, there is only one account on the computer at present. So here we use eth. Accounts [0] to extract the first account address. The eth.getbalance function is used to obtain the account balance, and the parameters are filled in the account address. The my variable here records the address of the first account

I hope my answer can help you

3. Ethereum is a distributed computing platform. It generates an cryptocurrency called ether. Programmers can write "smart contracts" on the Ethereum blockchain, and these Ethereum smart contracts will be executed automatically according to the code

what is Ethereum
Ethereum is often compared with bitcoin, but the situation is different. Bitcoin is a kind of cryptocurrency and distributed payment network, which allows bitcoin to be transferred between users

related: what is bitcoin? How does it work

Ethereum has a bigger goal. As Ethereum says, "Ethereum is a distributed platform running smart contracts.". These smart contracts run on "Ethereum virtual machine", a distributed computing network composed of all devices running Ethernet nodes

"distributed platform" means that anyone can set up and run an Ethereum node just as anyone can run a bitcoin node. Anyone who wants to run "smart contracts" on nodes must pay the operators of these nodes in ether, which is a cryptocurrency related to Ethereum. Therefore, the person running the Ethernet node provides computing power and gets paid in the Ethernet, which is similar to the way that the person running the bitcoin node provides hash power and pays in bitcoin

in other words, although bitcoin is only a blockchain and payment network, Ethereum is a distributed computing network, and its blockchain can be used for many other things. Details are provided in the Ethereum white paper

what is ether
Ethernet is a digital token (or cryptocurrency) related to Ethereum blockchain. In other words, Ethereum is the token and Ethereum is the platform. But now people often use these terms alternately. For example, coinbase allows you to buy Ethereum, which stands for Ethereum

this is technically "altcoin", which actually means a non bitcoin cryptocurrency. Like bitcoin, ether is supported by distributed blockchain - in this case, Ethereum blockchain

developers who want to create applications or Ethereum smart contracts on Ethereum blockchain need Ethernet token to pay for nodes to host it, while users of Ethereum based applications may need Ethernet to pay for services in these applications. People can also sell services outside the Ethereum network and accept Ethernet payments, or they can sell Ethernet tokens in cash - just like bitcoin

4. Generally speaking, undefined index is the exact writing problem in the process of writing. Notice generally prompts for errors that are not directly related to the execution of code, but don't forget that notice sometimes returns some rendant error information

5. How many account addresses can an Ethereum node have at most
A: generally, there is only one account address, otherwise there will be an error! Blockchain itself is unique. If there are multiple account addresses on one node, it violates the fundamental principle of blockchain!

6. The Internet has just begun, intelligent life coming

7.

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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