Ethereum offline signature 6
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"
Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency Ethereum. The concept of Ethereum was first inspired by bitcoin by vitalik buterin, a programmer, between 2013 and 2014, and now it's 2.0. Ethereum 2.0 is also something that the whole coin circle is waiting for. In order to celebrate the birth of the genesis block of eth2.0 on December 1, chinacoin officially supports the exchange of eth2.0 verification nodes at 17:00 Hong Kong time on November 20, 2020. It will invest its own eth in the verification node mining and exchange qeth to obtain liquidity. It will participate in the mining as soon as the exchange is received. Now it will give back to the user's welfare. The top 1000 eth enjoy the over exchange of qeth according to the ratio of 1:1.02. Compared with eth2.0, qeth has too many advantages: liquidity is guaranteed, users do not need to bear the technical cost, the threshold of participation does not need 32 eth, as low as 0.1eth, nodes are maintained by the platform, and the revenue is distributed according to eth2.0< br /> < br /> < br />
The digital currency wallet is the hardware wallet, which means that the private key of digital assets is stored in a single chip, isolated from the Internet, plug and play. Hardware wallet can't guarantee 100% security. For example, if a geek gets your hardware wallet and doesn't know your private key, it may be cracked by violence. It's just one of the safest storage methods compared to other storage methods
many block chain entrepreneurs at home and abroad are optimistic about the development of this field, so they begin to build more hardware wallets. In the case of the exchange being stolen a lot of money and the software wallet being stolen from time to time, many investors regard the hardware wallet as the last moat
extended information:
whether the hardware wallet is safe
the hardware wallet can not guarantee 100% security. For example, if a geek obtains your hardware wallet, it may be cracked violently even if it doesn't know your hardware wallet immediately. It's just one of the safest storage methods compared to other storage methods
of course, there are exceptions, such as you have unlimited brain power and never forget. It's better to save it anywhere than in your own mind
light wallets are good for imtoken, geekwallet, kcash, Cobo, etc.
Hardware wallets are good for ledger, trezor, etc., which involve large amount of digital currency or hold for a long time. Generally, hardware wallets are recommended
big body introces these personal good light wallets
1. Imtoken:
is a mobile light wallet app, which supports Eth and Ethereum erc2.0 standard tokens (such as EOS, DGD, SNT, qtum)
advantages: as Ethereum series light wallet, mtoken supports all the tokens of Ethereum erc2.0 standard, can control the miner's fee of each coin, can set the collection amount, and has convenient transaction record query, refreshing interface and easy operation, so it is suitable for ICO investors who need to receive a variety of erc2.0 standard tokens and trade infrequently
disadvantages: 1. The "discovery" mole of the wallet is not intuitive enough. 2. The tokens that can only be stored on the Ethereum platform, such as BTC and Neo, can't be stored. At the same time, the bifurcations of bitcoin can't be stored
2. Geek wallet
geek wallet is a simple and convenient light wallet, which supports the storage and management of mainstream digital currency assets such as bitcoin (BTC), lightcoin (LTC), Ethereum (ETH), EOS, usdt, etc. Using bip44 mnemonics, local private key, off-line signature and other security mechanisms, as well as mobile phone and computer al backup strategy, completely solve the loss of digital currency assets caused by hacker attacks, virus infection, mobile phone loss, forgetting mnemonics and other ways, and provide users with online Multi Chain digital assets one-stop management service. The platform also has tiaoshao market, which can carry out token trading of physical assets on the chain
advantages: it has high security factor, adopts local private key security mechanism, as well as mobile phone and computer al backup strategy, supports the current mainstream currency, and has a jump market on the platform, which can carry out token trading of physical assets on the chain
disadvantages: usdt transaction must use 0.0001 BTC as transaction handling fee, does not support some small currencies, page optimization is good, but the function is relatively few
3. Kcash
kcash is also a light wallet. At present, it supports BTC, ETH, LTC, etc, act and digital currency based on Ethereum and achain smart contract platform. Kcash has cross chain and cross contract technology, and the supported currencies are still increasing
advantages: as a Multi Chain Wallet, kcash supports multiple types of digital currencies and is very friendly to users who invest in multiple series of digital currencies. In addition, kcash also has the function of sending red packets, and in the future, it will launch currency transaction, bank card connection and other functions
deficiency: too many features lead to poor usability. In addition, there are some compatibility problems with Android versions. Some Android models will flash back when opening apps< Cobo
4. Cobo
Cobo is a professional digital asset management wallet, which can help you store your assets safely. The unique POS gain can help you increase the value of your assets. It supports more than 20 kinds of digital assets including eth, EOS and TRX, as well as more than 500 kinds of tokens
advantages: Cobo security is in the lead in the same level, using multiple security verification, hot and cold separation storage, HSM multi signature, Cobo provides you with stable income through intelligent voting, dpos vote pool, POS mining digital asset gain matrix
disadvantages: poor page optimization, complex functions, a little difficult to get started, and there is also a flash back problem of Android version
5. Ledger
Hardware wallet, which supports eth, BTC, zcash and other mainstream currencies, uses encryption chip technology to build security solutions for users, and is used to protect users' digital assets and block chain application security. This is a hardware bitcoin wallet specially designed for consumers. It provides enterprise level security hardware moles and hardware procts supporting the Internet of things
6, ledger
Hardware wallet, support eth, BTC, zcash and other mainstream currencies; Using encryption chip technology to build security solutions for users to protect users' digital assets and block chain application security. This is a hardware bitcoin wallet specially designed for consumers. It provides enterprise level security hardware moles and hardware procts supporting the Internet of things.
Recently, the new blockchain application "oasis" of xiaoman Finance (formerly Network Finance) was launched. This is another blockchain application scenario launched by xiaoman finance after leitzdog, aiming to build a financial service platform based on blockchain ecology in the financial field
at present, many users have started to settle in the oasis, and found that the oasis will proce crystal every day. So how should xiaoman oasis play?
in terms of playing methods, users can register as oasis residents with one click through the Internet wallet, "computing power" is the core ability of oasis residents to obtain "crystal", and "crystal" is the digital asset of oasis ecology, Oasis residents can improve their "computing power" by completing tasks, and computing power will automatically dig digital assets "crystal" for residents. The more computing power users accumulate, the more crystals they get. The total amount of crystal is constant every day, and the output is reced by half every two years. With the passage of time, it will be more and more difficult to obtain, and the early participation will have more advantages
at present, xiaoman oasis is in the internal test period, and the specific function of crystal has not been announced yet. However, the black diamond of Netease can be used for consumption and exchange on the planet. Xiaobian thinks that there is still a lot of room for imagination in the future of xiaoman oasis
Invitation Code: ws364vu
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
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)
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