Ethereum digital signature
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 />
It does not belong to MLM
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 proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, to the effect of "next generation cryptocurrency and decentralized application platform", and began to develop through crowdfunding in 2014. The market value of Ethernet currency is second only to bitcoin, and it is the second largest encrypted digital currency in the world
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bitcoin has created the first decentralized cryptocurrency, and has fully tested the feasibility and security of blockchain technology in more than five years. In fact, bitcoin's blockchain is a set of distributed database. If a symbol bitcoin is added into it and a set of protocol is specified, the symbol can be transferred safely on the database without trusting a third party. The combination of these features perfectly constructs a currency transmission system bitcoin network
however, bitcoin is not perfect, and the scalability of the protocol is a deficiency. For example, there is only one symbol in the bitcoin Network - bitcoin, and users can't customize other symbols. These symbols can represent the company's stocks or debt certificates, which will lose some functions
In addition, a stack based scripting language is used in bitcoin protocol. Although this language has some flexibility to realize functions such as multi signature, it is not enough to build more advanced applications, such as decentralized exchanges. Ethereum is designed to solve the problem of insufficient scalability of bitcoinThe 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
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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.
coinbase transaction is a special transaction that generates bitcoin "out of thin air". Only miners can write this kind of transaction, and the number of generated bitcoin is limited by rules (new currency reced by half for every 210000 blocks + transaction fee for this block)
however, the rules do not stipulate that the miner must take away all the rewards that can be taken, and can choose not to take them
therefore, a mine pool connected with the RSK side chain has made a bug before, forgetting to take away the reward and occupying a pit in a block for nothing, which is equivalent to destroying the corresponding amount of bitcoin, making the total amount of bitcoin decrease a little bit permanently
in addition, to spend a bitcoin, you only need to specify the transaction ID and output serial number
as like as two peas in multiple blocks repeatedly write identical coinbase transactions, the transaction ID is also repeated.
therefore, this kind of situation also occupies the pit of a block in vain, and permanently destroys the corresponding amount of bitcoin
it seems to me that this is still a security vulnerability, so the new version of bitcoin software later banned the writing of repeated coinbase transactions. But until now, there has been no ban on miners not getting their e rewards
generally speaking, a coin is controlled by a private key. If a coin is transferred to an address where no one knows the private key, it will be destroyed
if the owner does a good job in security, and the private key is not disclosed and cannot be guessed, but he accidentally loses the private key, it is equivalent to destroying all the coins he owns
there are only some special circumstances that require intentional destruction of coins
one is irreversibly converted into another kind of currency, such as the contract currency XCP attached to bitcoin and wormhole cash WHC attached to BCH
the second is to save certificates and data on the chain, such as the time stamp: panbiao.com/2013/08 /
and the crowd funding of the original Ethereum founding team: zhuanlan.hu.com/p/29
the private key is essentially a big number. Whoever knows this number can control the currency on the corresponding address. So the private key must be generated with reliable random number, otherwise it may be guessed and stolen
compared with the token, the address is the hash of the public key. There is no way to judge whether an address has a corresponding public key and private key (even if the public key is known, the corresponding private key cannot be known). Therefore, even if it is explicitly the address of "burned" token, the system does not prohibit the transfer in
strictly speaking, what locks the currency is a small program (script). This program takes the input as the public key and digital signature. First, check whether the public key hash is consistent, and then check whether the digital signature is valid. If it is valid, it will be verified and transfer is allowed; Otherwise, it will be judged that the transaction is illegal and refuse to package into the chain
it is the whole node software that explains and executes this program. It can be said that the software code of the whole node specifically defines a coin
however, the current situation is very embarrassing. Most miners do not run the whole node, only a few mines are running. The vast majority of users do not run the whole node, even if they run the whole node, they can only perform verification, no computing power, no block.
Jybusd: the lucky dollar is a kind of digital currency, but it has been proved to be a kind of digital currency fraud
digital currency investment needs to pay attention to the following matters:
1. Regular security platform
we must trade through regular digital currency investment platform. If we want to trade through digital currency investment, we can choose digital currency with business license and corresponding company service telephone, which will be relatively safe
2, a small amount of capital investment
investment in digital currency investment leverage investment risk is greater, novice early do not blindly pursue money and profit, can survive in this investment market is the most critical. At the same time, in order to prevent the loss of too much money after being cheated, we must keep an optimistic attitude according to our own situation, and we must participate in a small amount of money to rece the investment risk
3. If you are cheated, report to the police in time. Although the police may not help, but at least let the police on record, so as to recover the loss also has a certain help
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common digital currency:
1, bitcoin (BTC)
bitcoin the concept of bitcoin was first proposed by Nakamoto in 2009, which is a P2P digital currency based on SHA-256 algorithm. Point-to-point transmission means a decentralized payment system, The total issue amount is 21 million
2. Ethereum (ETH)
Ethereum is a public blockchain with smart contract function, and its founder is vitalik buterin
3. XRP
ripple is a decentralized asset transmission network, which is used to solve the asset conversion and trust problems between financial institutions and users
4. Bitcoin cash (BCH)
BCH is a kind of hard bifurcated bitcoin, which modifies the code of bitcoin, supports large blocks, and does not include segwit. To solve the problem of capacity expansion
5. Lightcoin (LTC)
lightcoin is derived from bitcoin, and its founder, Li Qiwei, went online on June 22, 2017
6. Dash
changed its name to dash after its original name was darkcoin. It is a digital currency that supports real-time transactions and aims at protecting users' privacy. Based on bitcoin, its unique two-layer network can make it more comprehensive for testing and updating
7. Xem
Xinjing coin is a new type of digital virtual coin based on Java, which adopts a new synchronous solution based on POI of proof of importance, and is said to be the first encrypted coin to realize multi signature at the block chain level
Small ant stock (NEO)Neo, using blockchain technology and digital identity for asset digitization, using intelligent contract for automatic management of digital assets, realizes a distributed network of "intelligent economy". In June 2015, GitHub launched a real-time open source project in 2014, with a total amount of 100 million. Founder Da Hongfei, Zhang Zhengwen
9. Monroe is a new generation of virtual currency based on cryptonote protocol and dedicated to privacy protection
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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