In every block of Ethereum
Ethereum is a new and open blockchain platform, which allows anyone to build and use decentralized applications running through blockchain technology in the platform. Like bitcoin, Ethereum is neither controlled nor owned by anyone - it's an open source project created by many people around the world
Different from bitcoin protocol, Ethereum is very flexible and adaptable. It's very easy to create new applications on the Ethereum platform. Anyone can use the applications on the platform safely 
Ethereum is a programmable blockchain. It does not give users a series of preset operations (such as bitcoin trading), but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications, including but not limited to cryptocurrency
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator
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"
this massive parallel operation throughout the Ethernet network is not to make the operation more efficient. In fact, this process makes computing on Ethereum slower and more expensive than on traditional computers. However, each Ethereum node runs Ethereum virtual machine in order to maintain the consistency of the whole blockchain. The consistency of decentralization makes Ethereum have high fault tolerance, zero downtime, and can keep the data stored on the blockchain unchanged and anti censorship
Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
a brief history of etheric Classics (etc)
etheric classics began with an unfortunate event
in May 2016, the decentralized autonomous organization (DAO) held a token sale with the goal of establishing a blockchain based venture capital to fund future decentralized applications (dapps) in the Ethereum ecosystem
basically, Dao is a complex smart contract that operates in a decentralized way - computer code that automatically performs tasks between multiple parties when conditions are met
despite its ambitious goals and successful token sales, Dao's code has a major vulnerability that allows attackers to steal eth from decentralized organizations
the attacker took advantage of this vulnerability in June 2016, triggering the infamous Dao hacking event, and maliciously stole eth worth about US $50 million
there is no doubt that Dao hacking has shocked Ethereum community and made eth price drop from $20 to $13
after the Dao hacking, the Ethereum community has to choose from three options
< UL >do nothing and try to bear the consequences of the attack
start soft bifurcation to recover funds
deploy a hard fork to recover the lost eth
both soft and hard bifurcations are significant network upgrades. However, soft fork allows users who are not upgraded to communicate with upgraded users, while hard fork is not backward compatible with previous versions
as developers realize that deploying soft forks will expose the network to distributed denial of service (DDoS) attacks, Ethereum community decides to initiate hard forks to recover the funds lost in Dao hacking attacks
although this scheme is supported by most people, a small number of people in Ethereum community oppose it. They think that "code is the law" and blockchain network should be unchangeable
the failure of both sides to reach an agreement on the solution eventually led to the fragmentation of Ethereum blockchain
those who tried to recover the lost eth chose the hard fork and opened the Ethereum (ETH) blockchain as we know it today, while another group stayed on the original Ethereum classic (etc) chain
what problems does ethereal classic solve Ethernet classic (etc) is a blockchain platform that allows developers to deploy smart contracts and dapps although this function is the same as Ethereum (ETH), etc blockchain has two main differences first of all, Ethereum classic community opposes tampering with distributed ledger and supports the view that "blockchain network cannot and should not be modified" secondly, although there is no rigid upper limit on the total supply of eth, it is allowed to create 230 million etc at most by adopting the monetary policy of constant supply as a bonus item, ethereal classic launched Atlantis hard bifurcation last year to increase the interaction with Ethereum and improve the privacy protection of transactions through ZK snarks the trading platforms recommended by ethereal classic etc are: Fire coin, okex, AAX, etc
although the pow mining mechanism is adopted, the block out mechanism of Ethereum is different from that of bitcoin. Due to the short block time of Ethereum, Ethereum is easy to form isolated blocks. Isolated blocks refer to the blocks that are not on the longest chain. Bitcoin's isolated blocks have no block rewards, but in Ethereum, isolated blocks can be referenced. The referenced isolated blocks are called "Uncle blocks", and their packaged data will also be recorded in the blockchain. Unlike bitcoin, Ethereum's TERT block has a reward, and each TERT block can get a reward of 4.375 Ethernet coins at most
Ethereum is a programmable and Turing complete blockchain development platform, which is equivalent to a decentralized global computer. In a programming system, there are usually some virtual machines to compile and execute. Java has JVM. In Ethereum, there is also Ethereum's virtual machine EVM, which can execute any complex algorithm code. Developers can use existing programming languages such as JavaScript or Python to create their own applications on Ethereum. Through Ethereum's virtual machine, you can easily issue digital assets, write smart contracts, set up and run decentralized applications, and set up decentralized autonomous organizations
eth is also known as the internal fuel of Ethereum. Unlike currency digital assets, Ethereum is not only used for transfer, but also for payment of smart contracts
in order to prevent the Ethereum blockchain from being full of junk contracts and junk applications, and to establish and run smart contracts on Ethereum, you must use eth to pay for smart contracts. For example, when you transfer your newly created digital assets on the Ethereum blockchain, you need to use eth to pay the handling fee instead of your newly created digital assets.
Ethereum is an open source public blockchain platform with smart contract function. It provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency ether (also known as "Ethereum")
The token on theblockchain is called ether, and the code is eth. It can be traded in many foreign exchange markets of cryptocurrency, and it is also the medium used to pay transaction fees and computing services on Ethereum
the concept of Ethereum was first proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, with the general meaning of "next generation cryptocurrency and decentralized application platform", and began to develop through ICO crowdfunding in 2014. As of February 2018, Ethernet is the second highest cryptocurrency in market value, second only to bitcoin
extended data:
Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
1. Blockchain links
as the name suggests, blockchain is a chain composed of blocks. Each block is divided into block head and block body (including transaction data). The block head includes the prevhash value (also known as hash value) of the previous block used to realize the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the head of the previous block, and the random number calculation rule determines which miner can obtain the right to record the block
2. Consensus mechanism
blockchain is accompanied by the birth of bitcoin, which is the basic technology architecture of bitcoin. Blockchain can be understood as an Internet-based decentralized accounting system. A decentralized digital currency system like bitcoin requires the consistency of accounting of honest nodes without a central node, which needs blockchain to complete. Therefore, the core of blockchain technology is a consensus mechanism to reach a consensus on the legitimacy of transactions between indivials without mutual trust without central control
there are four main types of consensus mechanisms in blockchain: pow, POS, dpos and distributed consistency algorithm
3. Unlocking script
script is an important technology to realize automatic verification and contract execution on blockchain. Every output of every transaction does not point to an address in the strict sense, but to a script. A script is like a set of rules that constrain how the receiver can spend the asset locked on the output
the validation of transactions also depends on scripts. At present, it depends on two kinds of scripts: Lock script and unlock script. Locking script is a condition added to the output transaction, which is realized by a script language and located in the output of the transaction. The unlocking script corresponds to the locking script. Only when the conditions required by the locking script are met can the assets corresponding to the script be spent, which is located in the input of the transaction. Many flexible conditions can be expressed by script language. Interpretation script is similar to the "virtual machine" in our programming field, which runs in every node of the blockchain network in a distributed way
4. Transaction rules
blockchain transaction is not only the basic unit of a block, but also the actual effective content recorded by the blockchain. A blockchain transaction can be a transfer, or the deployment of smart contracts and other transactions
as far as bitcoin is concerned, a transaction refers to a single payment transfer. The transaction rules are as follows:
1) the input and output of the transaction cannot be empty
2) for each input of a transaction, if its corresponding utxo output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is the transaction not recorded in the blockchain, and each input of the transaction should come from the confirmed utxo. If it is found in the current trading pool, it is Shuanghua trading
3) for each input in a transaction, the corresponding output must be utxo
4) each input unlocking script must verify the compliance of the transaction together with the corresponding output locking script
5. Transaction priority
the priority of blockchain transaction is determined by the blockchain protocol rules. For bitcoin, the priority of a transaction to be included in a block is determined by the time when the transaction is broadcast to the network and the amount of the transaction. With the increase of transaction broadcast time on the network and the increase of transaction chain age, the priority of transaction will be improved and eventually be included by the block. For Ethereum, the priority of the transaction is also related to the transaction fee that the publisher is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority that the transaction is included in the block
6. Merkle proof
the original application of Merkle proof is bitcoin, which was described and created by Satoshi Nakamoto in 2009. Bitcoin blockchain uses Merkle proof to store transactions in each block. So that the transaction can not be tampered with, but also easy to verify whether the transaction is included in a specific block
7. RLP
RLP (recursive length prefix) is one of the main encoding methods of object serialization in Ethereum. Its purpose is to encode the sequence of arbitrary nested binary data.
does each node have complete blockchain data? You mean a user node? A user node needs to keep the of the block head of the longest workload proof chain, so it knows the data of all the block heads. It can move forward to know all the data on the block chain, but not all of them are saved. A block header is very small, only 80 bytes, which can be saved completely, because the generation of nodes is very slow. Even with the passage of time, the amount is not too large now.
in today's mobile payment era, few people will use coins for payment . A lot of people, they think that mobile payment is more convenient, if you carry RMB, it will be very troublesome, so now less and less people use paper money to pay. In fact, the process of making paper money is also very complicated. The materials used to make coins are different metals. Compared with those rare metals, low-cost metals are more suitable for making coins
< / blockquote >and those rare metals, such as gold or silver, are suitable for making commemorative coins with collection value . In many countries, some of their currencies are made of alloy, because it is a very ideal material for coinage, and the hardness is improved by mixing with other metals. At the beginning of making coins, we should choose the materials and put the selected metals in the furnace for casting and melting. After many times of rolling in the rolling workshop, the thickness of the coin can meet the requirements of coins, and it can be made into semi-finished procts for further processing{ RRRRR}
with the progress of science and technology, now many mold making machines have become engraving machines for casting to replace the previous manual process . It can improve the accuracy to a certain extent. It used to take a whole day to manufacture, but now it can complete the remanufacturing of the mold within a few hours. After that, it can be pressed on the coin, and the coin will become the currency in circulation