PHP blockchain

1. The currency exchange platform is not bad, I play on it. It supports the legal currency transaction, with fast cash withdrawal speed and high quality currency. Now there is also the activity of bonus currency delivery

2. 1. bitcoin 2, Ethereum: Ethereum is a kind of digital token of Ethereum, which is regarded as "bitcoin version 2.0". Using blockchain technology different from bitcoin, "Ethereum" developers need to pay Ethereum (ETH) to support the operation of the application. Like other digital currencies, they can be traded on trading platforms. 3. lettercoin: lettercoin (LTC, currency symbol:?) It is a kind of network currency based on "point-to-point" technology and an open source software project under MIT / X11 license. It can help users make instant payments to anyone in the world. 4. Dogcoin: dogcoin, known as "dogcoin / dogcoin", 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 number of users. 5. Yuan Bao coin: Yuan Bao 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. 6. Diandiancoin: "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. 7. Katecoin: katecoin (KTC for short) is a virtual P2P digital currency that can be used all over the world. Point to point transmission means a decentralized payment system. 8. Quark coin: Based on six encryption algorithms (black, BMW, groestl, JH, keccak, skein), 9 rounds of super secure hash operation of virtual currency, 3 rounds of application of random hash function, quark coin 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. 10. Common coin: common coin, English name popular coin, short for POC, was born on March 7, 2014. The total POC is close to the world population (7.057 billion).

3.

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the quark blockchain team promised not to conct any pre digging and selling of points, let alone any fund-raising activities such as ICO and private placement

quark blockchain is a kind of blockchain based on PHP language, and ultimately hopes to provide distributed web, distributed storage and distributed streaming media playback services through blockchain technology

the goal is to build a blockchain project that belongs to everyone

4. curl方法，file_get_contents,

5. At present, there are not many videos on the market for systematic learning of blockchain, and self-learning of blockchain is still relatively rare. You can apply for classes. Black horse programmers will open a new blockchain discipline. Teachers will teach in an easy-to-understand way and explain in simple terms. You can certainly learn it.

6. Go language + blockchain training course:
from the characteristics of the language itself, go is a very efficient language, which highly supports concurrency. Go language itself pays more attention to distributed systems, and concurrency processing is relatively good, such as advertising and search, which are high concurrency servers
go language advantages:
excellent performance, can be directly compiled into machine code, does not rely on other libraries, go is extremely fast. Its performance is similar to Java or C + +
concurrency is supported at the language level, which is the biggest feature of go. It is born to support concurrency, and go is the concurrency supported in gene, which can make full use of multi-core and make it easy to use concurrency
the built-in runtime supports garbage collection, which is one of the features of dynamic language. Although GC is not perfect at present, it is enough to cope with most of the situations we can encounter, especially GC after go1.1
it's easy to learn. The authors of go language all have the gene of C, so go naturally has the gene of C. There are 25 go keywords, but the expressive ability is very strong. It almost supports most of the features you've seen in other languages: inheritance, overloading, object, etc
rich standard libraries, go has built a large number of libraries, especially the network library, which is also my favorite part< As like as two peas, br / > built-in powerful tools, Go language is built with many tools chain, the best should be gofmt tools, automatic formatting code, make team review become so simple, code format is exactly the same, it is very difficult to think differently.
cross platform compilation and fast compilation. Compared with the sluggish compilation speed of Java and C + +, the fast compilation time of go is a major efficiency advantage
disadvantages of go language:
package management: package management of go language is absolutely not perfect. By default, it has no way to make a specific version of the dependency library, nor can it create replicable builds. In contrast, python, node and Ruby all have better package management systems. However, with the right tools, the package management of go language can also perform well
lack of development framework: go language does not have a major framework, such as Ruby's rails framework, Python's Django framework or PHP's laravel. This is a heated discussion in the go language community, because many people think that we should not start with using frameworks. This is true in many cases, but if you just want to build a simple crud API, it's much easier to use Django / djrf, rails laravel, or Phoenix
exception handling: go language can help developers deal with compilation errors by simply returning errors (or call stack) through functions and expected calling codes. Although this method is effective, it is easy to lose the scope of the error, so it is difficult to provide meaningful error information to users. Error package can solve this problem by allowing us to add context and stack trace to return error
another problem is that we may forget to handle errors. Static analysis tools such as errcheck and megacheck can avoid these errors. Although these solutions are very effective, they may not be the right way.

7. Why not dig bitcoin BTC instead of bitcoin VTC? At present, many large-scale mines abroad have allocated one third of their computing power to dig special coins. What is the reason for this
let me analyze it:
1: bitcoin has been broken in China, and its price has dropped sharply, which is unexpected by the global mining pool
2: compared with the current mining cost of bitcoin, it makes money entirely by cheap electricity bills
3: there are only 21 million bitcoins, and most of them have been g up in the early stage, which makes it difficult to dig those bitcoins that have not been g up in the future, and there is too much competition. Many small mines are in a state of loss
and why do many well-known mines turn to TCD
first of all, bitcoin is the optimized and upgraded version of bitcoin, with a constant number of 100 million. The early mining is very good. Unlike bitcoin, which has too high cost and low cost performance ratio, it is appropriate to use bitcoin as a supplement to compare bitcoin. Bitcoin is used for large amount payment and bitcoin is used for small amount payment.

8.

Yes

use PHP code to define blocks:

class block {

public $prevhash

public $hash;

public $timeStamp;

public $data;

}

prevhash: the hash value of the previous block; Hash: hash value of the current block; Timestamp: the time stamp generated by the block; Data: data stored in the block; The fields prevhash, hash and timestamp are called block headers in the blockchain, and the hash value of the block is calculated by SHA-256 algorithm

extended data

the practical use and significance of blockchain:

blockchain is a decentralized distributed ledger. What is decentralization? There is no center, or everyone can be a center. This is different from the traditional way of centralization. Distributed ledger means that the storage of data is not only on each node, but each node will and share the data of the whole ledger

In addition, blockchain has the characteristics of disintermediation and information transparency. For example, for example, when we shop on Taobao, after we place the order, the cost we pay is first hit in Alipay. After we receive the courier and confirm the receipt, the money will be transferred to the seller's account. In the blockchain, buyers and sellers can trade directly without any platform as a third-party certification authority

the system will broadcast the transaction information of both parties. All hosts will record and back up the transaction data after receiving the information. If the order of one machine is wrong, the backup data of other machines will not be affected

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the concept of blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. Since it is a mode, it is not limited to language, only that language is more suitable

blockchain needs a lot of storage, calculation and transmission. PHP is not suitable for these characteristics, especially the efficiency of PHP

if you want to study this, look at the article of blockchain more:

understanding of blockchain,

51 lines of code to realize a simple PHP blockchain

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