Classical algorithm in virtual currency
1、 Different definitions:
1. virtual currency:
virtual currency refers to non real currency
digital currency:digital currency is an alternative currency in the form of electronic currency. Both digital gold coin and cryptocurrency belong to digiccy
3. Cryptocurrency:
cryptocurrency is a kind of transaction medium that uses cryptography principles to ensure transaction security and control the creation of transaction units
4. Token (token):
a kind of article whose shape and size are similar to currency, but the scope of use is limited and has no currency effect, and its token is the homonym of token in English
Second, the characteristics are different:1; It can also be said that virtual currency is personalized currency. In another way, it can also be called information currency
2. Digital currency:
is an unregulated and digital currency, which is usually issued and managed by developers and accepted and used by members of specific virtual communities
Cryptocurrency:cryptocurrency is based on the decentralized consensus mechanism, which is opposite to the banking and financial system relying on the centralized regulatory system
4. Token (token):
usually needs to be exchanged for money, used in shops, playgrounds, mass transportation and other places, as a voucher to use services and exchange goods
extended data
at present, digital currency is more like an investment proct, because it lacks a strong guarantee agency to maintain its price stability, and its role as a value measure has not yet appeared, so it can not be used as a means of payment. As an investment proct, digital currency cannot develop without trading platform, operating company and investment company
digital currency is a double-edged sword. On the one hand, the blockchain technology it relies on has been decentralized and can be used in other fields except digital currency, which is one of the reasons why bitcoin is popular; On the other hand, if digital currency is widely used by the public as a kind of currency, it will have a huge impact on the effectiveness of monetary policy, financial infrastructure, financial market and financial stability
litecoin (LTC), released on October 7, 2011, is the most valuable counterfeit coin at present, accounting for about 2% of BTC's market value. The current unit price is US $2.31, with a total currency value of US $38 million
this is also a distributed (decentralized) digital currency. Unlike the sha256 mining algorithm used by bitcoin, LTC adopts scrypt algorithm. Scrypt algorithm uses sha256 as its subroutine, and scrypt itself needs a lot of memory. Each hash is used as the seed of the input, and then it needs a lot of memory to store another pseudo-random sequence to generate the pseudo-random points of the sequence and output the hash value. In the mining of BTC (bitcoin), it is not enough to rely on simple graphics card mining (it takes about ten to dozens of days to dig a BTC with general configuration graphics card). The emergence of various expensive mining machines has raised the threshold for ordinary people to get BTC through mining, while LTC has certain advantages in using PC graphics card mining This passage comes from Zhihu.)
compared with BTC, litecain has made a little improvement in technology. If BTC is gold now, LTC is silver for the time being
the biggest advantage of litecoin is that it can confirm the authenticity faster. The virtual currency is designed and maintained by Charles Lee. Bitcoin transactions need to be verified, and the average verification time is more than 10 minutes. Most transaction websites need 1 hour to verify. The average transaction confirmation time of liteoin is 2.5 minutes. Developers claim that shortening the verification time increases the practicability of virtual currency. The bitcoin mining efficiency of customized machine and AMD GPU is the highest, making it almost unprofitable for miners using CPU mining. Litecain's mining excludes GPUs and custom processors, so it doesn't rely too much on a small number of professional miners
ppcoin
ppcoin (PPC) was released on August 19, 2012, which has improved the original technology of BTC. Use proof of make and add the concept of coin age
ppcoin is a bifurcated project of bitcoin, which aims to achieve energy efficiency and maintain the best performance of the original bitcoin as far as possible. The unit price of ppcoin is US $0.22 and the total currency value is US $4 million
ppcoin does not have a fixed upper limit of money supply, but it does not mean that ppcoin has obvious inflation compared with bitcoin. Bitcoin can be compared to gold. The annual inflation rate of gold is about 1-3%. Although gold has no known upper limit of money supply, we still know that it is a reliable scarce commodity
ppcoin has two types of casting: work certificate and equity certificate. The coinage rate of working proof is affected by Moore's law, which depends on the doubling of our working proof ability. What we all know is that Moore's law will eventually come to an end. By then, the ppcoin of inflation may be close to the gold level. The annual maximum inflation rate of certificate of equity is 1%. At the same time, ppcoin's transaction costs were destroyed to fight inflation. So on the whole, the coin design of ppcoin is still a very low inflation design in the future, which can be comparable with bitcoin<
ppcoin's reward is similar to lottery, which will determine the winning probability according to the number of ppcoin held by miners. Sunny king, one of the founders, said that their design is based on a new concept of long-term energy efficiency
terracoin
terracoin (TRC) was released on October 26, 2012, with a total currency of 42 million. The speed of each block is 2 minutes, slightly faster than LTC. There is not much special in technology, similar to the proction of BTC halved every four years
however, the operation team seems to have a strong business background and may be better than other bitcoins in circulation. The development of virtual currency is getting more and more attention. Now some teams with business background will accelerate the development of virtual currency
namecoin
namecoin is a distributed domain name system based on bitcoin technology. Its principle is the same as bitcoin. The first release date of this open source software is April 18, 2011
namecoin is generated from an original block which is different from bitcoin's main trading block. It uses a new blockchain, which is independent of bitcoin's blockchain. Because it is based on bitcoin, the security, distribution, robustness, encryption and migration of domain names are guaranteed mathematically. You can dig bitcoin and namecoin at the same time
this project was discussed and proposed by bitdns, which is mainly dissatisfied with the defects of DNS. The only top-level domain name of namecoin is. Bit. It costs namecoin to register a. Bit domain name.
network virtual currency can be roughly divided into
the first category is familiar game currency. In the era of stand-alone games, the protagonist accumulates money by knocking down the enemy, entering the gambling house to win money, and using these to buy Herbs and equipment, but it can only be used in his own game console. At that time, there was no "market" between players. Since the establishment of Internet portal and community, the realization of game networking, virtual currency has a "financial market", players can trade game currency
the second type is the special currency issued by the portal website or instant messaging service provider, which is used to purchase the services in the website. The most widely used is Tencent's q-coin, which can be used to purchase membership, QQ show and other value-added services
the third kind of virtual currency on the Internet, such as bitcoin (BTC), Fuyuan coin (FTC), Wright currency (LTC), etc. bitcoin is an electronic currency proced by open-source P2P software. Some people also translate bitcoin as "bitcoin", which is a kind of network virtual currency. It is mainly used for Internet financial investment, and can also be directly used in daily life as a new currency.
elliptic curve digital signature algorithm is mainly used in the generation process of bitcoin public key and private key, which is the cornerstone of bitcoin system. SHA-256 hash algorithm is mainly used in the workload proof mechanism of bitcoin
the principle of bitcoin generation is the special solution generated by complex operation, and mining is the process of finding the special solution. However, the total number of bitcoin is only 21 million, and with the continuous mining of bitcoin, the more difficult it will be to proce bitcoin, and the cost of acquiring bitcoin may be higher than the price of bitcoin itself
the bitcoin block consists of a block header and the transaction list contained in the block. The size of the block header is 80 bytes, which is composed of 4-byte version number, 32 byte hash value of the previous block, 32 byte Merkle root hash, 4-byte timestamp (current time), 4-byte current difficulty value and 4-byte random number. A block header with a fixed length of 80 bytes is the input string used to prove the workload of bitcoin. Constantly change the random number in the block header, that is, the value of nonce, and do double sha256 operation on the block header after each change, and compare the result value with the target value of the current network. If it is less than the target value, the problem is solved successfully, and the workload is proved to be complete
the essence of bitcoin is actually the unique solution of a set of equations generated by a bunch of complex algorithms. Bitcoin is the first distributed virtual currency in the world, which has no specific distribution center. The network of bitcoin is composed of all users, because there is no center to ensure the security of data.