Ethereum hash algorithm
mainstream digital currencies such as bitcoin, Puyin, Laite, ethereum and dogcoin all exist in wallets, and wallets existed before the release of such currencies.
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. Blockchain is an important concept of bitcoin,
in essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of information of bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
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most blockchain public chains are limited by scalability. The biggest feature of blockchain technology is decentralization, which requires that all accounts in the network need to deal with the accounting process. Distributed accounting has high security, low misoperation rate, political neutrality and correctness
however, blockchain technology embraces these features at the same time, sacrificing scalability, unable to meet the personalized supervision, and slightly insufficient in protecting data privacy. Moreover, with the increase of the number of ledger, the interaction delay will increase exponentially, that is to say, the more ledger in the blockchain network, the higher the delay
You can refer to the following, according to some commonly used graphics cards in the Internet bar market, sort out the price and calculation power of a related graphics card, as well as the expected return to the current period, It can be used as a reference:
{rrrrrrr}
power consumption: 243w
computing power: 22.4m
price of graphics card: 1999 yuan
quantity of eth g every 24 hours: 0.015
revenue generated every 24 hours: 24.48 yuan
expected payback time: 81.66 days
power consumption: 159w
computing power: 24.3m
price of graphics card: 1599 yuan Yuan
number of eth g every 24 hours: 0.017
revenue generated every 24 hours: 27.9 yuan
estimated payback time: 57.31 days
total power consumption: 171w
computing power: 24.4m
price: 1999 yuan
number of eth g every 24 hours: 0.017
revenue generated every 24 hours: 27.87 yuan
estimated payback time: 71.73 days
Video card (graphics card) full name display interface card, also known as display adapter, is the most basic configuration of computer, one of the most important accessories. As an important part of the computer host, the graphics card is the equipment of digital to analog signal conversion, and it undertakes the task of output display graphics
the graphics card is connected to the main board of the computer, which converts the digital signal of the computer into an analog signal for the display. At the same time, the graphics card still has the ability of image processing, which can help the CPU work and improve the overall running speed. For those engaged in professional graphic design, graphics card is very important. Civil and military graphics chip suppliers mainly include amd (ultra micro semiconctor) and NVIDIA (NVIDIA). Today's TOP500 computer, including graphics card computing core. In scientific computing, graphics card is called display accelerator
do you remember what the consensus mechanism of bitcoin is? The consensus mechanism of bitcoin is pow. To put it simply, the more work you do, the higher the amount of computation you pay, the more likely you will be the first to find the correct hash value, and the more likely you will be rewarded with bitcoin
however, there are some defects in the pow of bitcoin, that is, it is too slow to process transactions, and miners need to constantly collide hash values through calculation, which is costly and inefficient. Friends who are interested in blockchain knowledge should see such a saying:
in order to make up for the deficiency of bitcoin, Ethereum has proposed a new consensus mechanism, called POS (this is the abbreviation of English, which means "proof of equity", also translated into "proof of equity")
POS simply means the same as its literal meaning: equity, equity. The more currency you hold, the more equity you have, the higher your equity
Ethereum's POS means that the more money you hold, the longer you hold it, the less difficult it will be to calculate and the easier it will be to mine
in the initial setting of Ethereum, Ethereum hopes to build a relatively stable system by using POW in the early stage, then graally adopt POW + POS, and finally completely transition to POS. So, it's true that the consensus mechanism of Ethereum is POS, but POS is only a plan or goal at the beginning of Ethereum's release. At present, Ethereum has not yet transitioned to POS, and the consensus mechanism adopted by Ethereum is still pow, that is, the pow of bitcoin, but it is slightly different from the pow of bitcoin
the amount of information here is a bit large,
the first information point is that the consensus mechanism currently adopted by Ethereum is also pow, but it is slightly different from the pow of bitcoin. So, what's the difference between the pow of Ethereum and bitcoin: in short, the mining difficulty of Ethereum can be adjusted, but the mining difficulty of bitcoin can't be adjusted. Just like our college entrance examination, because the teaching situation and the number of students in different provinces are not the same, so the college entrance examination is divided into national papers and provincial independent proposition
Ethereum said that I am in favor of the topic by region. Bitcoin said: No, it must be the same volume in the whole country. The difficulty is the same for everyone
the popular explanation is that bitcoin uses computer computing power to do a lot of hash collisions, enumerate various possibilities to find a correct hash value. The Ethereum system has a special formula to calculate the difficulty of each block. If a block is verified faster than the previous block, Ethereum protocol will increase the difficulty of the block. By adjusting the block difficulty, the time needed to verify the block can be adjusted
according to the Ethereum protocol, the dynamic adjustment method of difficulty is to make the time interval of creating new blocks in the whole network 15 seconds, and the network uses 15 seconds to create blockchain. In this way, because the time is too fast, the synchronization of the system is greatly improved, and it is difficult for malicious participants to launch 51% (that is, more than half) of the computing power to modify historical data in such a short time
the second information point is: in the initial setting of Ethereum, we hope to achieve the transition from POW to
POS through phased upgrade
dating back to 2014, at the beginning of Ethereum's launch, the team announced that the launch of the project would be divided into four stages, namely, Froniter, homestead, metropolis and serenity. In the first three stages, the consensus mechanism adopts pow (workload proof mechanism), and in the fourth stage, it switches to POS (equity proof mechanism)
on July 30, 2015, the first phase "frontier" of Ethereum was officially released. This phase is only suitable for developers. Developers can write smart contracts and decentralized application DAPP on Ethereum network, and miners begin to enter Ethereum network to maintain network security and get Ethereum coins. The leading-edge version is similar to the beta version, proving whether the Ethereum network is reliable or not
on March 14, 2016, Ethereum entered the second stage of "homeland". In this stage, Ethereum provides the wallet function, so that ordinary users can easily experience and use Ethereum. There is no obvious technology improvement in other aspects, but it shows that Ethereum network can run smoothly
in September 2017, Ethereum has reached the third stage of "metropolis"“ "Metropolis" is composed of Byzantine and Constantinople. The goal of this stage is to introce the hybrid chain mode of POW and POS, so as to prepare for the smooth transition from POW to POS. This is the latest popular "Ethereum Constantinople upgrade". In the Constantinople upgrade, Ethereum will make some changes to the underlying protocols and algorithms to lay a good foundation for the implementation of POW and
POS
how much reward will Ethereum get for mining? Miners who win the block creation competition will get the following income:
1. Static reward, 5 ethereums
2. The fuel cost in the block, i.e. gas, we talked about in the last issue
3. As a part of the block, it includes the extra reward of "Uncle block". Uncle is uncle of uncle, and each uncle block can get 1 / 32 of the mining reward as a reward, that is, 5 times 1 / 32, which is equal to 0.15625 ethereums. Here, let's briefly explain the concept of "TERT block". The concept of "TERT block" was proposed by Ethereum. Why should we introce the concept of TERT block? This also starts with bitcoin. In the bitcoin protocol, the longest chain is considered absolutely correct. If a block is not part of the longest chain, it is called a "orphan block". An isolated block is a block, which is also legal, but it may be found later, or the network transmission is slower, and it does not become part of the longest chain. In bitcoin, the solitude is meaningless and will be discarded later, and the miners who find the solitude will not receive mining related rewards
however, Ethereum does not think that isolated blocks are worthless, and Ethereum system will give rewards to miners who find isolated blocks. In Ethereum, isolated blocks are called "Uncle blocks", which can contribute to the security of the main chain. Ethereum's ten second block interval is too fast, which will rece the security. By encouraging the use of tertiary blocks, the main chain can obtain more security guarantees (because the isolated block itself is legal). Moreover, paying the tertiary block can also stimulate the miners to actively mine and actively use tertiary blocks. Therefore, Ethereum thinks that it is valuable.
in fact, blockchain uses the basic principles of modern cryptography to ensure its security mechanism. The knowledge system involved in the field of cryptography and security is very complicated. Here, I only introce the basic knowledge of cryptography related to blockchain, including hash algorithm, encryption algorithm, information digest and digital signature, zero knowledge proof, quantum cryptography, etc. Through this lesson, you can learn how to ensure the confidentiality, integrity, authentication and non repudiation of the blockchain using cryptography technology
basic course lesson 7 basic knowledge of blockchain security
1. Hash algorithm (hash algorithm)
hash function (hash), also known as hash function. Hash function: hash (original information) = summary information. Hash function can map any length of binary plaintext string to a shorter (generally fixed length) binary string (hash value)
a good hash algorithm has the following four characteristics:
1. One to one correspondence: the same plaintext input and hash algorithm can always get the same summary information output
2. Input sensitivity: even if the plaintext input changes slightly, the newly generated summary information will change greatly, which is greatly different from the original output
3. Easy to verify: plaintext input and hash algorithm are public, anyone can calculate by themselves, and whether the output hash value is correct
4. Irreversibility: if there is only the output hash value, the hash algorithm can never dece the plaintext
5. Conflict avoidance: it is difficult to find two plaintexts with different contents, but their hash values are the same (collision)
for example:
hash (Zhang San lent Li Si 100000 yuan for 6 months) = 123456789012
such a record as 123456789012 is recorded in the account book
it can be seen that hash function has four functions:
simplify information
it is easy to understand, and the information after hashing becomes shorter
identification information
you can use 123456789012 to identify the original information, and summary information is also called the ID of the original information
hidden information
the account book is a record like 123456789012, and the original information is hidden
verification information
if Li Si cheated that Zhang San only lent Li Si 50000 when repaying, both parties can verify the original information with the hash value of 123456789012 recorded before
hash (Zhang San lent Li Si 50000 for 6 months) = 987654321098
987654321098 is completely different from 123456789012, which proves that Li Si lied, Then the information can't be tampered
common hash algorithms include MD4, MD5 and Sha series algorithms, and Sha series algorithms are basically used in mainstream fields. Sha (secure hash algorithm) is not an algorithm, but a group of hash algorithms. At first, it was SHA-1 series, and now the mainstream applications are sha-224, SHA-256, sha-384 and sha-512 algorithms (commonly known as SHA-2). Recently, Sha-3 related algorithms have been proposed, such as keccak-256 used by Ethereum
MD5 is a very classic hash algorithm, but unfortunately, both it and SHA-1 algorithm have been cracked. It is considered by the instry that its security is not enough to be used in business scenarios. Generally, sha2-256 or more secure algorithm is recommended
hash algorithm is widely used in blockchain. For example, in blocks, the latter block will contain the hash value of the previous block, and the content of the later block + the hash value of the previous block will jointly calculate the hash value of the later block, which ensures the continuity and non tamperability of the chain< Encryption and decryption algorithm is the core technology of cryptography, which can be divided into two basic types: symmetric encryption algorithm and asymmetric encryption algorithm. According to whether the key used in the encryption and decryption process is the same or not, the two modes are suitable for different needs, just forming a complementary relationship, and sometimes can be combined to form a hybrid encryption mechanism
symmetric cryptography (also known as common key cryptography) has the advantages of high computational efficiency and high encryption strength; Its disadvantage is that it needs to share the key in advance, which is easy to leak and lose the key. The common algorithms are des, 3DES, AES and so on
asymmetric cryptography (also known as public key cryptography) is different from the encryption and decryption key, and its advantage is that it does not need to share the key in advance; Its disadvantage is that it has low computational efficiency and can only encrypt short content. Common algorithms include RSA, SM2, ElGamal and elliptic curve series. Symmetric encryption algorithm is suitable for the encryption and decryption process of a large number of data; It can't be used in signature scenario: and it often needs to distribute the key in advance. Asymmetric encryption algorithm is generally suitable for signature scenario or key agreement, but it is not suitable for large amount of data encryption and decryption< Third, information digest and digital signature
as the name suggests, information digest is to hash the information content to obtain a unique digest value to replace the original and complete information content. Information digest is the most important use of hash algorithm. Using the anti-collision feature of hash function, information digest can solve the problem that the content has not been tampered
digital signature is similar to signing on paper contract to confirm contract content and prove identity. Digital signature is based on asymmetric encryption, which can be used to prove the integrity of a digital content and confirm the source (or non repudiation)
we have two requirements for digital signature to make it consistent with our expectation for handwritten signature. First, only you can make your own signature, but anyone who sees it can verify its validity; Second, we want the signature to be only related to a specific file and not support other files. These can be achieved by our asymmetric encryption algorithm above
in practice, we usually sign the hash value of information instead of the information itself, which is determined by the efficiency of asymmetric encryption algorithm. Corresponding to the blockchain, it is to sign the hash pointer. In this way, the front is the whole structure, not just the hash pointer itself< Zero knowledge proof means that the verifier can make the verifier believe that a certain conclusion is correct without providing any additional information to the verifier
zero knowledge proof generally meets three conditions:
1. Completeness: authentic proof can make the verifier successfully verify
2. Soundness: false proof can not make the verifier pass the verification
3. Zero knowledge: if you get proof, you can't get any information other than the proof information from the proof process< With more and more attention paid to the research of quantum computing and quantum communication, quantum cryptography will have a huge impact on the information security of cryptography in the future
the core principle of quantum computing is that qubits can be in multiple coherent superposition states at the same time. Theoretically, a large amount of information can be expressed by a small number of qubits and processed at the same time, which greatly improves the computing speed
in this way, a large number of current encryption algorithms are theoretically unreliable and can be cracked, so the encryption algorithm has to be upgraded, otherwise it will be broken by quantum computing
as we all know, quantum computing is still in the theoretical stage, which is far from large-scale commercial use. However, the new generation of encryption algorithms should consider the possibility of this situation.
ETL is Ethereum digital currency
Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized Ethereum virtual machine to process point-to-point contract through its special cryptocurrency ether (ETH)
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 ICO crowdfunding in 2014
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features:
1. Decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
abey blockchain technology is from Ciprian pungila & amp; Co., Ltd., two doctors in the Department of artificial intelligence, Department of computer science, School of mathematics and information, Western University of timishwara, Romania; Vorel negru's own research project. Constant lightweight block technology and multi-layer programming and extended blockchain solution are adopted. The scale of abey's blockchain remains unchanged, with only 50 active blocks. Abey blockchain technology is suitable for the use of e-money in e-commerce system for mass transactions, and has multi-level, scalability and security, and can be programmed
analysis of abey blockchain Technology