Is bitcoin scripting language Turing complete

1. Smart contract & quot The term "smart contract" can be traced back to at least 1995 and was proposed by the prolific interdisciplinary legal scholar Nick Szabo. He mentioned the concept of smart contract in several articles published on his website. His definition is as follows:
& quot; A smart contract is a set of promises defined in digital form, including the agreements on which the contract participants can execute these promises& quot;
let's explore the meaning of his definition in more detail
commitment
a set of commitments refers to the (often mutual) rights and obligations agreed by contract participants. These commitments define the nature and purpose of the contract. Take a sales contract as a typical example. The seller promises to deliver the goods and the buyer promises to pay a reasonable price
digital form
digital form means that contracts have to be written into computer-readable code. This is necessary, because as long as the participants reach an agreement, the rights and obligations of smart contract establishment are executed by a computer or computer network
to further explain:
(1) when will the parties to the smart contract reach an agreement? The answer depends on the specific smart contract implementation. Generally speaking, the contract is discovered when the parties are committed to the execution of the contract by installing the contract on the contract host platform< (2) contract execution
& quot; Execute & quot; And the real meaning of it also depends on implementation. Generally speaking, implementation means active implementation through technical means
(3) computer readable code
in addition, the contract needs specific & quot; Digital form & quot; Very much depends on the agreement that the parties agree to use
protocol
protocol is technical implementation, on this basis, the contract commitment is realized, or the contract commitment is recorded. Which agreement to choose depends on many factors, the most important of which is the nature of the assets being traded ring the performance of the contract
take the sales contract as an example. Suppose that the participants agree to pay in bitcoin. The chosen protocol will obviously be bitcoin protocol, on which the smart contract will be implemented. Therefore, the contract must use & quot; Digital form & quot; It's bitcoin scripting language. Bitcoin scripting language is a non Turing complete, imperative, stack based programming language, similar to forth.

2. Open source software, see: https://github.com/bitcoin/bitcoin/

3. Ethereum project draws lessons from the technology of bitcoin blockchain and expands its application scope. If bitcoin is a special calculator using blockchain technology, Ethereum is a general-purpose computer using blockchain technology. In short, Ethereum = blockchain + smart contract
compared with bitcoin, the biggest difference of Ethereum is that it can support a more powerful scripting language (technically speaking, Turing's complete scripting language), allowing developers to develop any application and implement any smart contract on it, which is also the most powerful point of Ethereum. As a platform, Ethereum can be compared with Apple's app store, on which any developer can develop applications and sell them to users. Each type of financial contract can be written as a smart contract in the form of program code<

the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system.

4. Illegal fund-raising is not a real virtual currency. A very significant feature of deceiving "virtual currency" is the unilateral rise of investment income. The total amount of real virtual currency is limited, and the price fluctuates. However, the price of virtual currency under the illegal fund-raising scam tends to rise unilaterally, and the assets of investors' books have been increasing. Once the scam can not continue, These fake virtual currencies are worthless, and investors have nothing to lose. At present, in addition to bitcoin, there are eth Ethereum, usdt TEDA, inmi and other regular currencies.

5. In short, a group digs bitcoin on the computer, which is equivalent to a big mine.

6. I've used this machine of my colleagues. The image quality seems not as good as Sr1, but it's OK
the size of the sensor is 1 / 5.5 inch CCD, which is too small
60g hard disk, is it necessary to make it so large
as a new hard disk recording camera, the technology is not very mature, and there are still many problems, such as the problem of shockproof, the problem of hard disk virus...
although the price is still very attractive, I still think it is more reliable to buy a DV camera in one or two years

the domestic price of sr80 ranges from 6800 to 7200, without invoice
personally, I think sr60 is more cost-effective. 30g hard disk is enough. Sr60 is only about 5700 in China

well, let's see what you can do with this machine. For ordinary household use, 30g of storage space is enough. The recording format is MPEG2. It can record 440 minutes in HQ mode, 650 minutes in SP mode and 1250 minutes in LP mode. Isn't that enough? If you are traveling or scientific research for a long time, I suggest you buy 60g, so that the recording time will be doubled, you can shoot for a long time, and you don't have to import it to the computer frequently

image quality largely depends on the camera lens. Whether it is sr80 or sr60, 1 / 5.5-inch single-chip CCD is very common, and it is not the best t * lens in Zeiss lens. The imaging quality is only average, not as good as the Sony ads boast

Sr1 can support 1080i HD model, 1 / 3 "crystal clear vid CMOS sensor, Carl & Chen 8226; Zeiss vario sonnar t * lens, these are incomparable to SR series

although this Sr1 is sold at around 12000 in China, it's a bit high, but you should be aware of the development trend of the camera field. The era of high-definition has come. CCTV will open three sets of high-definition channels to report the 2008 Beijing Olympic Games
you can't buy a DV in one or two years. In the long run, I suggest you buy Sr1
since you are studying abroad and usually use the camera only for entertainment, there is no need to buy Sr1. Sr60 / 80 is enough
it's OK for camera enthusiast users to choose Sr1

the disadvantages of sr80 are also obvious. No matter how large the hard disk space is, it is limited. When the storage is nearly full, you must find a way to import the material to the computer, and the DV tape can be stored for a long time; In addition, aibvane also said that the hard disk has a certain life span. Once there is a problem with the hard disk, it is difficult to repair it; In addition, the minimum illumination is much higher than the nominal 7 lux, and the shooting effect is not good in dim light or at night
it also has the outstanding advantages of electronic anti shake function; In addition, hard disk storage saves money on DV tape
I checked the official specification sheet of Sony's machine. It is used normally and the operating temperature is 0 ° C to + 40 ° C. Storage temperature: - 20 ° C to + 60 ° C
it is recommended that you use the machine outdoors in bad weather as little as possible, or make a heat preservation cover for the machine to wrap it up, which can protect the machine from the cold to a certain extent.

7. Ethereum is also a proct of blockchain 2.0, which is an open intelligent contract complete solution. Bitcoin is the most important application of blockchain 1.0, which completes currency and payment transactions well. But when we need to record and transfer more complex asset types, we need the third step - a more powerful scripting system - to finally achieve Turing completeness (the ability to run any currency, protocol or blockchain). Ethereum is a blockchain based project, which aims to provide a Turing complete scripting language and Turing complete platform

blockchain 1.0 mainly refers to bitcoin. Blockchain 2.0 extends to all assets, while blockchain 3.0 goes beyond currency, finance, even commerce, and all areas of our lives, including politics, social relations, ecation, medical care, etc. According to the prediction and conception of people in the instry, the era of blockchain 3.0 will be realized in the next five years. At that time, blockchain will be recognized and accepted by all the public like the Internet, thus completely subverting our lives

McKinsey has submitted a technical report on blockchain to the Federal Insurance Advisory Committee of the United States. The report calls 2009-2016 the "Dark Age" and believes that all blockchain solutions ring this period are based on bitcoin, and the new era of blockchain will begin in 2016. At that time, the application of blockchain will become unprecedented. Applying an original sentence in McKinsey report: Based on the current development speed of blockchain, we believe that blockchain solutions may realize their full potential in the next five years.

8. All computable problems can be calculated. Such a virtual machine or programming language is Turing complete.

9. From a very strict theoretical point of view, the answer is: No. Because PHP and python are Turing complete languages, theoretically you can't find a thing that Python can do but PHP can't
Turing refers to the computing power of a universal Turing machine, such as a programming language or any other logic system, in the theory of computability. In other words, the system can simulate with general Turing machine. The word comes from mathematician Alan Turing who introced the concept of Turing machine
although Turing opportunities are physically limited by storage capacity, Turing completeness usually refers to a general physical machine or programming language with unlimited storage capacity
in short, all computable problems can be calculated. Such a virtual machine or programming language is Turing complete
Turing equivalence02turing equivalence02turing completeness
we often see Turing equivalence02turing completeness in programming language books or articles, but we don't know the exact meaning and difference of these two words. In particular, many books or articles often mix these two words, so I wonder if they mean the same thing. I used Google to search for it. Unfortunately, the Chinese results were basically useless. There was only one article reprinted in cyberspace, which was written by a foreigner, and it was all in English. After a brief look, I felt that it was not very clear, so I checked the English wiki. To get back to the point, let's take a look at two paragraphs of wikinet:
in02computing theory, a system of data manipulation rules (such as an02instruction set, a02programming language, In computability theory, a system of data operation rules (such as instruction set, programming language, programming language, etc.) can be used to simulate any single taped 02turing machine and thus in principle any computer Cellular automata (CA) is called Turing complete or general computational if and only if it can be used to simulate a single band Turing machine< br />In computability theory, there is a closely related concept known as Turing equivalence. Two computers P and Q are called Turing equivalent if P can simulate Q and Q can simulate P. Thus, a Turing-complete system is one that can simulate a Turing machine, But the term is most often used to mean Turing equivalent to a Turing machine. When P and Q are Turing equivalent, P can simulate Q and Q can simulate P. Therefore, a Turing complete system can simulate a Turing machine, but this term (Turing equivalent) is often used to refer to the equivalent of a Turing machine
then let's look at the formal definition of these two words in computable Theory:
Turing completion: a computational system that can compute every Turing computable function 02is called Turing complete (or Turing powerful). Alternatively, such a system is one that can simulate a02universal Turing machine.
Turing equivalence：A Turing-complete system is called Turing equivalent if every function it can compute is also Turing computable; i.e., it computes precisely the same class of functions as do02Turing machines. Alternatively, a Turing-equivalent system is one that can simulate, and be simulated by, a universal Turing machine. (All known Turing-complete systems are Turing equivalent, Which adds support to the 02church – Turing thesis.
Turing equivalence: a Turing complete system is called Turing equivalent if any function it can compute is Turing computable. That is to say, the functions that it can calculate are exactly the same as those that Turing machine can calculate. In other words, a Turing equivalent system is a system that can simulate a universal Turing machine and can also be simulated by a universal Turing machine All known Turing complete systems are Turing equivalent, which increases the support for the church Turing thesis)
through the above analysis, we can clearly know the meaning and relationship of the two words. Turing equivalence has two meanings: one is that two computing systems have the same computing power in terms of computability; The other, also commonly used, means that the computing power of a system is the same as that of a general Turing machine (in the sense of computability). Turing completeness refers to a computing system that can simulate a general Turing machine. All known Turing complete systems are Turing equivalent, which increases the support for the church Turing thesis. Therefore, in the existing computer system (programming language, instruction set, etc.), using Turing equivalence and Turing completeness is one meaning.