Digital currency time
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
in addition, Q currency, Shanda currency, starting point currency and various online game currencies are also virtual currencies.
among them, the leading ones of domestic virtual currency are Yuanbao coin, Ruitai coin and bitcoin. These are sentimental currencies.
if it is POW algorithm: such as bitcoin. Users tend to synchronize the new chain with the best computing power. And each trade has a delay of six blocks. So every time we make a fake block, we usually need to make all the POWs of the first six blocks at the same time, and the accumulated POWs of these six blocks need to be higher than those of the real main chain (the main chain is jointly maintained by honest users) to ensure success every time, so we need to master 51 computing power
XTT refers to the US dollar notes used by Americans before
on the front of the dollar bill, the main picture is the portrait of a person, and the main color is black. The main design of the back is architecture, and the main color is green, but there are few differences in the colors of different editions; In addition, e to the dollar green is made of a kind of SAP ink, so each time the sap quality is different, so the color is slightly different. The signature above is the signature of the Minister of finance, and the Ministry of finance is different in different issuing years
extended information:
XTT dollar notes are made of cotton fiber and hemp. Long cotton fiber makes paper not easy to break, good ink absorption, not easy to fade. Hemp fiber is strong and tenacious, which makes the paper stiff, rable and fluffy. It has certain resistance to water, oil and some chemical substances. There is no whitening agent added to the dollar paper, which is white and does not reflect light under the purple light
in addition, the dollar bill will display black and green with different light angles. The main patterns of US dollar are engraving, gravure printing, library printing and serial number printing. After the 1990 edition, miniature characters were added around the portrait window below
the magnetic material is added to the ink. The real US dollar bill is made of special ink such as fluorescent ink and magnetic ink, so the green badge and green number on the right side of the front of the US dollar bill can leave "green mark" on the paper after being wiped on the white paper
hash value of previous block: prev_ Hash
the hash tree value of the transaction to be written: Merkle_ Root
update time: ntime
current difficulty: nbits
the process of mining is to find x to make
sha256 (version + prev)_ hash + merkle_ root + ntime + nbits + x )) < Target
the range of X in the above formula is 0 ~ 2 ^ 32, which can be calculated according to the current difficulty. In addition to x, you can also try to change Merkle_ Root and ntime. Because of the hash feature, finding such an X can only be brute force search
once you find x, you can broadcast a new block, and other clients will verify whether your block is legal. If your block is accepted, the first transaction in each block must be to send the newly generated 25 bitcoins to an address. Of course, you will set the address to your own address to get the 25 bitcoins< Every transaction record of bitcoin from the beginning to now has been saved on the network. The whole bitcoin network maintains a huge transaction record file (about 12g now). The average update cycle of this file is 10 minutes. The newly added transaction record is called a block, and this huge file is composed of a series of blocks, called block chain.
Why are 25 bitcoins
this is the rule. At first, there are 50 bitcoins. For each half of the remaining bitcoins, the income will be halved. In this way, the total amount of bitcoins that can be generated will approach 21 million. If you still claim to have g up 50 bitcoins, it will not be accepted by other clients, and the block will be g up in vain
how to ensure that the average update cycle is 10 minutes
the smaller the target, the more difficult it is to solve X. for every 2016 blocks (about 14 days) generated, the network will adjust the target according to the average interval of new blocks generated ring this period
is it the fastest person who always solves it first
No. You always want to take the mining income as your own, so when everyone calculates, the address to send the mining income is different, so Merkle_ Root is different, that is to say, everyone starts to solve from a different initial state
how to solve it at the same time
there will be a fork in the block chain. Some clients accept a and some accept B. until a branch becomes longer, everyone will choose the longer branch. If what you dig is unfortunately not selected, your mining income will be invalid
since I choose a longer branch, how can I solve it with very low difficulty
the client finds the most difficult and longest branch among many branches
are these calculations wasted
if you want to spend a sum of money twice, you need to do so. Dig a new block, but hide not broadcast, and continue to mine. Find merchant a, pay bitcoin, and let others on the network dig the block and write the transaction record. Find merchant B, pay bitcoin, and write the block you g. If you can get two blocks first and broadcast them, everyone will take your longer branch as the current block chain, and the bitcoin received by merchant a will not be recognized. In this way, the probability of successful attack depends on the speed of hash calculation. If the computing power of the whole network is high enough, the success rate of such attacks is very low or the cost is very high.
In essence, time chain is a relational model expressed by time axis, which is an objective law of internalization in the field of economic activities. The deeper the understanding of time chain, the easier it is to obtain a better way of resource allocation, and the more waste can be reced to the greatest extent
time chain refers to the change of the distribution structure of matter and energy flowing into the network with time. The source is a sentence in the article "time chain analysis of material and energy flow in ecological network" published by Han Boping in Acta ecologica Sinica in 1995. This is a sentence that can be found in the academic field to clearly describe the concept of time chain
the actual time resources that can be mined and reorganized in the supply chain:
1. The time rhythm of raw material suppliers and channel distributors
2. The selection time and interface specification time of the third party and the fourth party, such as warehousing, transportation, communication, management consulting, law, customs, etc
3. The supply capacity of upstream (time decrease)
4, downstream service time (time reced)
5. The cost, frequency and shortest cycle of different types of suppliers
extended data
time is a very broad consensus based and equal attribute. With the support of blockchain technology, time public chain has become a reality. Because the fairest thing in the world is time. Everyone has 24 hours a day, and no one has more seconds than anyone else. The idea that everyone is equal before time has been deeply rooted in the hearts of the people. The emergence of time chain will take time as the anchor of value, and human's desire to take time as the general equivalent will soon become a reality
timecoin is the world's first bottom public chain that uses blockchain technology and decentralization mechanism to reshape the value of time. It creatively uses pot algorithm and time partition mode to create the most widely recognized time token in the world, and opens up a new era of post blockchain
under the idea that everyone is equal before time, the time public chain team found that there is a serious time zone attribute TZ (time zone) in the whole world. In different time zones, even between different indivials, there will be some positive and negative deviations in the value of time. Aiming at the existing problems, the time public chain team uses time x (time difference variable), a secondary digital currency unit, to solve the value exchange between time citizens with different time reference systems, and can extend to the value exchange of different time zones