Keccak Ethereum
according to the notice and announcement issued by the people's Bank of China and other departments, virtual currency is not issued by the monetary authority, does not have legal compensation and mandatory monetary attributes, is not a real currency, does not have the same legal status as currency, cannot and should not be used as currency in the market, and citizens' investment and transaction of virtual currency are not protected by law
response time: December 10, 2020. Please refer to the official website of Ping An Bank for the latest business changes
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1. Bitcoin
the concept of bitcoin was first proposed by Nakamoto in 2009. According to Nakamoto's ideas, open source software was designed and released, and the P2P network was built on it. Bitcoin is a kind of P2P digital currency. Point to point transmission means a decentralized payment system
2, Ethereum
Ethereum (ETH) is a kind of digital token of Ethereum, which is regarded as "bitcoin version 2.0". It adopts the blockchain technology "Ethereum", which is different from bitcoin. Developers need to pay for eth to support the operation of the application. Like other digital currencies, they can be traded on trading platforms
3. Litecoin
litecoin It is a kind of network currency based on "peer-to-peer" technology. It is also an open source software project under MIT / X11 license. It can help users make instant payments to anyone in the world
lightcoin is inspired by bitcoin (BTC) and has the same implementation principle in technology. The creation and transfer of lightcoin is based on an open source encryption protocol and is not managed by any central organization
Dogcoin, which is called dogcoin / dogcoin by some people, was born on December 8, 2013. Based on the crypt algorithm, dogcoin is the second largest virtual currency in the world after bitcoin in terms of the number of usersdigital currency is a global common currency initiated by non-governmental organizations. It does not belong to a certain country, but belongs to all mankind. It has the advantages of fast global transfer. For example, it can remit money from China to the United States in a few seconds, and the cost is low, and the total amount will not be increased at will like legal money, so the total amount is relatively stable
Yuanbao coin is a virtual digital currency similar to bitcoin. The founder of yuanbaocoin is a group of bitcoin enthusiasts and the earliest supporters. However, after seeing the problem of bitcoin, he decided to do his best to develop an electronic currency suitable for Chinese people with the latest technology Ppcoin was pre released by sunny king on August 11, 2012 and officially released on August 19, 2012. Ppcoin's biggest innovation is that its mining method combines POW workload proof and POS equity proof. POS mining method only needs ordinary computers and clients to process transactions and maintain network security, so as to achieve the purpose of energy saving and security Katecoin (KTC) is a virtual P2P digital currency that can be used all over the world. Point to point transmission means a decentralized payment systemin businesses that support Kat coin consumption, you can directly use Kat coin for consumption payment
8, quark money
based on six encryption algorithms (black, BMW, groestl, JH, keccak, skein), nine rounds of super secure hash operation of virtual money, three rounds of application of random hash function, quark money has unique technical specifications
9, infinity coin
infinity coin (IFC) is a new digital currency, which has more circulation advantages than bitcoin, and fills the short board of bitcoin in the field of commercial circulation and promoting commercial operation
one transaction of infinite coin needs three confirmations, each confirmation takes 30 seconds, and the transaction confirmation speed is very fast. Because bitcoin transaction needs 6 confirmations, which takes about 1 hour, and lightcoin transaction takes 15 minutes, infinite coin is used in daily common transactions, which is more practical
Common coin, English name popular coin, or POC, was born on March 7, 2014. The total POC is close to the world population (7.057 billion)POC is a super secure hash operation based on nine rounds of six encryption algorithms (Blake, BMW, groestl, JH, keccak, skein), which is suitable for CPU mining. It generates a block every 15 seconds, with a total of 7.057 billion (close to the world population)
extended data
virtual currency refers to non real currency. Well known virtual currency, such as network company's network currency, Tencent company's Q currency, Q point, Shanda company's voucher, Sina's Micro currency (used for micro games, Sina reading, etc.), chivalrous Yuanbao (used for chivalrous road game), silver pattern (used for bixue Qingtian game)
the popular digital currencies in 2013 are bitcoin, Leyte coin, infinite coin, quark coin, zeta coin, BBQ coin, pennies (Internet), invisible gold bar, red coin and prime currency. At present, hundreds of digital currencies are issued all over the world. Popular in the circle & quot; The legend of "bitcoin, Wright silver, infinite copper, pennies aluminum"
1. Litcoin (LTC) is an improved version of digital currency inspired by bitcoin (BTC). It was designed and implemented by a programmer who worked in Google. It was released on November 9, 2011. Lightcoin and bitcoin have the same implementation principle in technology, but the creation and transfer of lightcoin is based on an open source encryption protocol, which is not managed by any central organization
2. Sunshine coin (SSC for short) is sponsored by Liu Chunyang, vice president of Jinhua express delivery Association of Zhejiang Province, instrial entrepreneur and philanthropist of express delivery instry. As a legal person, Zhejiang Dongyang Yueyin Technology Co., Ltd. is registered with the formal instry and Commerce Bureau, with a registered capital of 10 million yuan. With this as the backing and support, the sunshine elite team affiliated to the company launched the first virtual coin sunshine coin
The English name of Vicat is onecoin, which is a kind of Internet virtual currency term created by the government and is suspected of pyramid selling fraudin 2017, CCTV announced the list of 350 fund pyramid schemes, with Vicat in the list
in May 2018, Zhuzhou County Procuratorate of Hunan Province prosecuted the last four suspects involved in the third batch of the "3.15" Vicat money online pyramid scheme case supervised by the Ministry of public security to the court
4. Amazon coin
Amazon announced in early February 2013 that it is expected to launch Amazon coins in the United States in May 2013. Amazon coins is a new virtual currency that allows U.S. users to buy apps, games and props in the kindle fire. Amazon will provide tens of millions of US dollars of Amazon coins at that time to let users try and consume the apps, games and props in the app on the kindle fire for free
5. Eth is a kind of digital token of Ethereum, which is regarded as "bitcoin version 2.0". It adopts the blockchain technology "Ethereum", which is different from bitcoin. It is an open-source public blockchain platform with intelligent contract results, and a resonance network composed of thousands of computers around the world. Developers need to pay eth to support the application. Like other digital currencies, ether currency can be bought and sold on the trading platform
1. Q coin
Q coin, referred to as QB, also known as QQ coin, Tencent Q coin, etc. Usually its exchange rate is 1q currency = 1 RMB, with Tencent paipai net transactions are generally 10% off
QB is a virtual currency launched by Tencent, which can be used to pay for QQ bank number, QQ member service and other services. Tencent q-coin, through the purchase of QQ card, telephone recharge, bank card recharge, network recharge, mobile phone recharge card, one card recharge card and other ways to obtain
The face value of QQ card is 10 yuan, 15 yuan, 30 yuan, 60 yuan, 100 yuan and 200 yuan respectivelythere is another kind of electronic cryptocurrency, qqcoin, which is not related to each other
2. Litecoin
litecoin, abbreviated as LTC, currency symbol: Ł; It is a kind of network currency based on "peer-to-peer" technology. It is also an open source software project under MIT / X11 license. It can help users make instant payments to anyone in the world
lightcoin is inspired by bitcoin (BTC) and has the same implementation principle in technology. The creation and transfer of lightcoin is based on an open source encryption protocol and is not managed by any central organization
3, infinite coin
infinite coin (hereinafter referred to as IFC) is a new digital currency, which has more circulation advantages than bitcoin, and fills the short board of bitcoin in the field of commercial circulation and promoting commercial operation. The positioning of unlimited money is to serve the daily life of small transaction payment
one transaction of infinite coin needs three confirmations, each confirmation takes three seconds, and the transaction confirmation speed is very fast. Because bitcoin transaction needs 6 confirmations, which takes about 1 hour, and lightcoin transaction takes 15 minutes, infinite coin is used in daily common transactions, which is more practical
infinite coin was released on June 5, 2013. Based on scrypt POW algorithm. A block is generated in 30 seconds. In the initial block, there are 524288 infinite coins in each block. After that, for every 86400 blocks generated, the number of coins in the block is halved, with a total of 90.6 billion. The difficulty of mining is adjusted every hour
Quark coin is not the currency in real life, it exists safely in the computer of global networkquark network is protected by six most advanced encryption algorithms to ensure that it can become a digital ledger. The whole network uses each of the six functions to generate a proof of work, and the coin maker must "verify" these transactions to ensure that each coin increase is real and effective
only regular computer can participate in ensuring that it can maintain a highly secure peer-to-peer network, which makes it more decentralized
quark coins can only be g up through the CPU of regular computers. In the first 36 weeks, a total of 247605120 quark coins will be g out. Since March 30, 2014, the annual quark coins set at 1050000 can enter the market through "digging", and the block reward will never be less than one, which is currently two
Zetacoin is an open-source digital currency based on SHA-256 algorithm. The initial coin mining is 160 million coins, and the subsequent annual inflation is a better incentive, To keep the hash of the network is not pure transaction cost The total number ofzetacoin is 160 million, 1000 zets per block and half of 80640 zets per block
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.