Ethereum broadcasting

1. Ethereum is registered in the United States

2.

in terms of cloth storage and mining, I recommend Heshu hardware wallet and jiajiabao intelligent home miner. The core advantage of the proct is safety

take sum hardware wallet as an example. The advantages of sum hardware wallet are as follows:

1. The private key seed is encrypted layer by layer, physically isolated and never touched the Internet.

firstly, when creating the wallet, the seed password is generated and stored in the local encryption chip, and the 10 bit payment password is required

then, the transaction is made in the wallet. At this time, the user needs to enter the payment password to obtain the private key to digitally sign the transaction, and the transaction is completed. In addition, the private key seed is permanently stored in the chip, which is physically isolated and never touches the Internet. There is no need to worry about my password being stolen by hackers

Second, the bank system verifies the financial level motherboard and encryption chip

uses the bank system to verify the financial level motherboard, and the private key seed is stored in the chip. If the proct is stolen or lost, and destroyed by malicious violence, the chip will trigger a self destruct circuit, and immediately permanently and irrecoverably delete all the information in the area

Third, it supports the withdrawal of global bitcoin ATM, which is convenient and fast

the reason why digital assets attract the attention of many fields in the world is that it is creating a global fast circulation, and the larger the circulation field is, the wider the scope is, and the higher its use value is. The core of digital assets is the medium it acts on among currencies. The Heshu wallet has built-in many mainstream exchanges in the world. It can trade digital assets anytime and anywhere. With one machine in hand, it can walk around the world without worry, and no longer have to worry about exchanging foreign currency

Different from conventional digital wallets, multi signature wallets need the authorization of multiple key holders to transfer digital currency, so the security of multi signature wallets is higher. Ordinary Wallet: a wants to transfer a bitcoin to X. A only needs his signature (using the private key) to complete the transaction. Sum Wallet: if a wants to transfer a bitcoin to x, a multi signature verification is set (at least two signatures of Abc3 indivials are required to transfer the money), then a needs B or C to complete the signature (using the private key) when a wants to transfer the money to X. I hope I can help you. Thank you

3. I plan to start a series to talk about architecture. My previous experience is mainly in the area of Internet architecture. Recently, I am sorting out and analyzing the architecture of bitcoin, Ethereum and EOS, so I am going to write a series of articles to talk about the understanding of Internet architecture and blockchain architecture. It will be divided into four articles: 1. Internet proct architecture, 2. Bitcoin architecture analysis, 3. Ethereum architecture analysis, 4. EOS architecture analysis
there is no central server in Ethereum. Instead, there are many equal nodes connected by P2P protocol, which store all the data in many nodes. When a user initiates a transaction, the transaction will be broadcast out through P2P protocol. The miner node verifies, packages and further broadcasts the transaction to the whole network. After confirmation in the blockchain, the operation is considered to be unchangeable
in the articles on blockchain on the Internet, the two words distributed and decentralized are mentioned, sometimes slightly different, sometimes mixed. The author thinks that if we want to distinguish accurately, the distributed system emphasizes that multiple components work together by sending messages, and the decentralized system emphasizes that there is no central node to control the operation of the whole system. Therefore, we think that Ethereum is both decentralized and distributed, or running a decentralized program on a distributed platform.

4. At present, their common point is blockchain + government affairs, but the application fields involve different scenarios. Personally, I don't think it's comparable. For the moment
according to the report, Zhejiang blockchain government platform is mainly engaged in blockchain bills, especially medical bills. The public platform of Changsha's SMIC blockchain mainly focuses on government information disclosure, government affairs handling, intellectual property protection, judicial expertise, finance and so on, but it has not involved the medical bills yet.

6. Fund stock and virtual currency are totally different concepts. Compared with fund, fund is the simplest. You only need to understand the history of fund managers and profit management companies. You can find some well-known large funds that are relatively standardized. Generally, the risk is not too big, but you don't have to expect too high returns. After all, the scale of the fund is large, It must be the first factor of safety.
compared with funds, stocks are more risky. After all, stocks fluctuate a lot. There are thousands of stocks. Even if the index rises, the stocks you buy may fall instead. Of course, the stocks you buy are much stronger than the index.
virtual currency is another concept. A few years ago, virtual currency was quite popular, However, since September 2017, the people's Bank of China, China Banking Regulatory Commission, China Securities Regulatory Commission, China Insurance Regulatory Commission, State Administration for Instry and commerce, etc. have jointly issued an announcement on preventing the financing risk of token issuance. As a result, the virtual currency has been comprehensively rectified. The virtual currency can no longer be exchanged in China, and all transactions are overseas, The risk is uncontrollable
the relevant information can be obtained through network query
personal opinion, for reference only

7. The first method is to use grep and cut values
the second method is to use grep and awk (the default separator is the space) values
the third method is to use grep and awk (multiple separators)
the fourth method is to use sed and awk
the fifth method is to use grep and awk (multiple separators and plus sign +)
the sixth method is to use awk (separators and their values) Line)
the seventh method: grep network card file
the eighth method: head line awk segmentation

if you don't understand anything, you can read the book "this is how to learn Linux", which is very suitable for novices to learn Linux.

8. Return the result of ifconfig
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

9. Now we are all concerned about Ethereum. How to trade Ethereum? I think we all want to know something, so let's make it up here to introce a lot of content about how to trade ether currency? The most intuitive explanation of Ethereum's transaction is the message and signed packet sent from an external account to another account on the blockchain<

contains the following contents:
sender's signature
receiving address
number of transferred digital currency, etc.
transactions on Ethereum need to pay fees, which is different from bitcoin. Ethereum has fixed this link, so this indirect understanding is a security error of Ethereum, It can prevent a large number of meaningless transactions and ensure a certain degree of security. In particular, the creation, execution and call of smart contracts need to consume costs, so it can also ensure the stability of the whole system and prevent some meaningless malicious behaviors on the chain
transaction handling fee
the core of Ethereum is EVM, Ethereum virtual machine, so the bytecode executed in EVM has to pay for it. That is, we often see the concepts of gas, gas limit and gas price
gas: literally, it means gasoline. Ethereum needs gas to run just like everyday cars. Gas is the basic unit for calculating consumption in a transaction. There is a list to intuitively see the gas consumption of operation in Ethereum:
the specific content of gas consumption of operation
the default cost of step 1 execution cycle
stop0 termination is free
suicide0 is the internal data storage space of the smart contract account. When the contract account calls the suicide() method, the value will be set to null<
sha320 encrypts and decrypts
sload20 obtains
sstore100 in the fixed memory and inputs it into the fixed memory
balance 20 account balance
create100 creates a contract
call20 initializes a read-only call
additional cost paid for memory expansion
consumption of each byte of data or code in txdata5 transaction process
transaction 500 transaction At present, the cost of contract creation 53000 homestead is adjusted from 21000 to 53000
so some companies or indivials feel that blockchain technology is disintermediated and does not need a central server. This development mode is relatively cheap, but in fact, the development of blockchain is not cheaper than those of traditional software development before
gas price: literally, it's like going to a gas station, what's the price of gasoline today. A gas price is the unit price, so your transaction cost = gas * gas price, and then you pay in ether. Of course, you think I don't want to pay fees. You can set gas price to 0, but the choice is in the hands of miners, and miners have the right to choose to accept transactions and charge fees. The simplest way to think about it is very difficult for a miner to accept a transaction with a very low price. In addition, the default gas price of Ethereum is 1wei
gas limit: literally, it is the limitation of gas. Limitation is necessary. Without limitation, there will be no constraint. This gas limit has two meanings. First of all, for a single transaction, this indicates how much gas the initiator of the transaction is willing to pay at most. The initiator of the transaction needs to set it when initiating the transaction. There is also a gas limit for blocks. A single block also has a gas limit
suppose several scenarios to illustrate the use of gas:
if the user sets the gas limit, then in the transaction process, if your actual consumed gas is used
if the user sets the gas limit, then in the transaction process, if your actual consumed gas is used & gt; Gas limit, then the miner must find that your gas is insufficient, and the transaction cannot be executed. After that, the transaction will be rolled back to the state before execution. At this time, the miner will charge gas price * gas limit
the gas limit of the block. There is a gas upper limit in the block, and different gas limits specified by the user will appear in the received transactions. Then the miners will choose according to the gas limit of the block limit and "reasonably" choose the packaged transaction
specific transaction
the transaction on Ethereum can be a simple transfer of Ethernet currency, and it can also be a code message of smart contract. List a table to see the specific content of the transaction:
code content
from the address of the transaction initiator, cannot be empty, and the source is not unreasonable
to the address of the transaction receiver (this can be empty, which means the creation of a contract)
value the number of Ethernet coins transferred
data field. When this field exists, it means that a transaction is a transaction that creates or invokes a smart contract.
gas limit literally means the limit of gas. The limit is necessary. If there is no limit, there will be no constraint. This gas limit has two meanings. First of all, for a single transaction, this indicates how much gas the initiator of the transaction is willing to pay at most. The initiator of the transaction needs to set it when initiating the transaction. There is also a gas limit for blocks. A single block also has a gas limit
gas price a gas price is the unit price, then your transaction cost = gas * gas price, and then you pay in ether. The default gas price of Ethereum is 1wei
nonce is used to distinguish the identity of the transaction issued by the user
hash transaction ID is a hash value generated from the above information, which is the three parts of
R, s and V transaction signature. The private key of the transaction initiator generates the hash signature
there are three types of transactions
transfer: simple and clear transfer of Ethernet currency on Ethereum, similar to bitcoin, a transfers a certain amount of Ethernet currency to B. This kind of transaction includes: the number of initiator, receiver and value of the transaction, and others like gas limit, hash and nonce will be generated by default. So you will see a piece of code:
Web3. Eth. Sendtransaction ({from: & quot; Address of transaction originator;, To: "address of transaction receiver", value: quantity})
smart contract creation: to create a smart contract is to deploy the smart contract to the blockchain, then to is an empty field at this time. The data field is the code to initialize the contract. So you can see the code:
Web3. Eth. Sendtransaction ({from: & quot; Address of transaction originator;, data: " contract binary code"});
smart contract execution: if the contract is created and deployed on the blockchain, the execution will add the to field to the address where the smart contract is to be executed, and then the data field will be used to specify the transfer of methods and parameters to be called, so you can see the code:
Web3. Eth. Sendtransaction ({from: & quot; Address of transaction originator;, To: "address of contract executor", data: "transfer of called methods and parameters"})
the above are roughly the types of transactions
transaction confirmation
like bitcoin, Ethereum transaction can only be confirmed after subsequent block confirmation and node synchronization. The simple understanding is to dig out more blocks and confirm the transaction after verification. Ethereum often has congestion, so sometimes it needs to wait for confirmation
transfer and contract transaction flow
first, transaction initiator a initiates a transfer transaction, Then the sending format is as follows:
code details
from the address of the transaction initiator
to the address of the transaction receiver
value the number of Ethernet coins transferred
the amount of gasgas
the unit price of gas pricegas
data the message sent to the receiver
nonce transaction number
node verification: a node in Ethereum network will receive the message sent by A, Then check whether the message format is valid, and calculate the gas limit. At this time, go back to verify a's Ethereum balance. If the balance is insufficient, an error will be returned and will not be processed. Once the message sent by a passes the verification of the node, the node will put the transaction into the transaction storage pool. And broadcast to the blockchain network
miner verification: the miner must package when writing to the blockchain. When the miner receives the transaction sent by a, it will package together with other transactions, and the ordinary transfer transaction can be packaged. Then the transaction called by the contract needs to execute the calling contract code on the miner's local EVM, and the gas consumption is checked ring the code execution. Once the gas is consumed, it will be rolled back. If the gas is enough, the extra gas will be returned. And broadcast to the blockchain network
other nodes: repeat the node verification steps, and then the contract will also perform verification on the local EVM. Synchronize the blockchain after verification
first, initiator a initiates a transaction request to create a smart contract. The format is as follows:
code details
address of the transaction initiator
to0
value number of Ethernet coins transferred
quantity of gasgas
unit price of gas pricegas
data contract code
nonce transaction number
node verification:
a node in Ethereum network will receive the message sent by a to check whether the transaction is valid and whether the format is correct, Verify the transaction signature. Calculate gas, determine the address of the originator, and then query the balance of ether currency in account a. If the balance is insufficient, an error will be returned and will not be processed. Once the message sent by a passes the verification of the node, the node will put the transaction into the transaction storage pool. And broadcast to the blockchain network
miner verification:
if the miner packages the transaction, the contract account will be created according to the transaction cost and contract code, and the contract will be deployed in the account space. Here we say the contract address (the address of the smart contract account has the address of the initiator and the random number of the transaction as the input, and then generated by the encryption algorithm). After the transaction is confirmed, the address of the smart contract will be returned to a. And broadcast to the blockchain network
other nodes:
repeat the node verification steps, verify the block, update a's smart contract transaction in the node's memory pool, synchronize the blockchain, and deploy the smart contract in its own local blockchain.

10. The configuration of the first network card in Linux system
description of ifcfg-eth0 configuration parameters in Linux:
ifcfg-eth0 is in / etc / sysconfig / network scripts,
its configuration is as follows:
device = physical device name
IPADDR = IP address
netmask = mask value
Network = network address
broadcast = broadcast address
gateway = gateway address
onboot = [yes | no]
userctl = [yes | no] (whether non root users can control the device)
bootproto = [none | static | BOOTP | DHCP] (boot) No protocol | static allocation | BOOTP protocol | DHCP protocol)
hwaddr = MAC address
some parameters are not required
the original configuration is as follows:
device = eth0
bootproto = DHCP
onboot = yes
in this case, the NIC is not activated
the modified configuration is as follows:
device = eth0
bootproto = static
broadcast = 192.168.129.128
IPADDR = 192.168.129.2
netmask = 255.255.255.0
Network = 192.168.129.0
onboot = yes
in this way, the network card can be activated every time it is turned on.