How blockchain guarantees uniqueness

❶ How blockchain is applied

1. Financial field:

Blockchain has potential in financial fields such as international exchange, letter of credit, equity registration and stock exchange huge application value. The application of blockchain technology in the financial industry can eliminate the need for third-party intermediaries and achieve point-to-point direct connection, thereby greatly reducing costs and completing transaction payments quickly.

2. IoT and logistics:

Blockchain can also be naturally combined in the IoT and logistics. Through blockchain, logistics costs can be reduced, the production and delivery process of items can be traced, and the efficiency of supply chain management can be improved. This field is considered to be a promising application direction of blockchain.

3. Public service field:

Blockchain is closely related to people’s production and life in public management, energy, transportation and other fields, but the centralized nature of these fields is also It brings some problems, which can be transformed with blockchain. The decentralized and fully distributed DNS service provided by the blockchain can realize the query and resolution of domain names through the point-to-point data transmission service between each node in the network, which can be used to ensure that the operating system and firmware of an important infrastructure are not If tampered, you can monitor the status and integrity of the software, detect bad tampering, and ensure that the data transmitted by the system using IoT technology has not been tampered with.

4. The field of digital copyright:

Through blockchain technology, works can be authenticated to prove the existence of works such as text, video, and audio, and to ensure the ownership of works. Authenticity and uniqueness. After the work is confirmed on the blockchain, subsequent transactions will be recorded in real time, realizing the full life cycle management of digital copyright, and can also be used as a technical guarantee in judicial evidence collection. For example, MineLabs, a startup company in New York, USA, has developed a blockchain-based metadata protocol. This system called Mediachain utilizes the IPFS file system to realize copyright protection of digital works, mainly for copyright protection applications of digital pictures.

5. Insurance field:

In terms of insurance claims, insurance institutions are responsible for fund collection, investment, and claims, often with high management and operating costs. Through the application of smart contracts, neither the policyholder’s application nor the approval of the insurance company is required, as long as the claim conditions are triggered, the policy will automatically settle the claims. A typical application case is LenderBot, which was launched in 2016 by blockchain companies Stratumn, Deloitte, and payment service provider Lemonway. It allows people to register for customized micro-insurance products through the chat function of Facebook Messenger and exchange them between individuals. High-value items are insured, and the blockchain replaces the third-party role in loan contracts.

6. Public welfare field:

The data stored on the blockchain is highly reliable and cannot be tampered with, and is naturally suitable for use in social welfare scenarios. Relevant information in the public welfare process, such as donation projects, fundraising details, fund flow, recipient feedback, etc., can be stored on the blockchain, and conditionally transparent and publicized to facilitate social supervision.

❷ How blocks are connected to form a blockchain

How does a blockchain ensure that the blocks are connected in sequence?
A blockchain is formed by connecting a series of blocks generated using a cryptographic algorithm. Each block is filled with transaction records, and the blocks are connected in sequence to form a chain-like structure, which is the blockchain large ledger.
Taking Bitcoin as an example, when miners generate a new block, they need to calculate the new hash value and random number based on the hash value of the previous block, the new transaction block and the random number. That is to say, each block is generated based on the data of the previous block, and this mechanism ensures the uniqueness of the blockchain data.
Because the slight change in the transaction record will completely change the result of the hash value, miners cannot cheat when competing for computing power. The data starts to calculate the random numbers that meet the conditions, which ensures the fairness of mining.

❸ Is the timestamp in blockchain technology unique?

Each block generated by timestamping is unique.
Jinwowo Group analyzes that the timestamp in the blockchain exists in the blockchain from the moment it is generated. It corresponds to the authentication of each transaction record, proving the authenticity of the transaction record.
The timestamp is directly written in the blockchain, and the blocks that have been generated in the blockchain cannot be tampered with, because once tampered, the generated hash value will change and become invalid data.

❹ How to use blockchain technology to confirm rights and deposit certificates

Innovation is the source of development, and intellectual property protection is to protect and stimulate innovation, thereby promoting economic and social progress and development.

Taking eBaoquan’s blockchain intellectual property protection platform – Microcopyright as an example, Microcopyright will knowThe combination of intellectual property protection and digital technology, using the characteristics of blockchain storage stability and not easy to tamper, stores the work data on the blockchain in the form of Hash encryption for blockchain confirmation, helping users to register the relevant information of the work in the chain.

❺ How does blockchain solve the problem of product traceability

Wang Chain Technology uses blockchain technology and uses alliance chain nodes to circulate commodity raw materials The information of the process, production process, commodity circulation process, and marketing process is integrated and written into the blockchain, and the tamper-proof property of the blockchain is used to realize the traceability of one item, one code and the whole process of authentic products

❻ Why Virtual currency is the only meaning of the existence of the blockchain

Why do you say that the virtual currency is the only meaning of the existence of the blockchain
Blockchain is already a well-known term, and some people even assert that, In the future, everything in human society will be based on blockchain. But if you ask what kind of technology blockchain is, the explanations of various “experts” can be said to be vague: some pile up terms that are incomprehensible to ordinary people, some talk about its potential applications, and some simply call it the “fourth industrial revolution”—— As for the nature of the blockchain, we still don’t know much about it.
It’s not hard to guess why. In terms of functionality, the blockchain is nothing more than a public database encrypted in a special way. This unsexy concept cannot be used for hype. Of course, the blockchain is so attractive, its connotation and extension cannot be as nutritious as its function. To make it clear, we need to understand a lot of information beyond the technical ontology, and the most important one is the virtual currency represented by Bitcoin.
The Pain Point of Blockchain
Five years ago, not many people in the world knew what a blockchain was. As the underlying technology of Bitcoin, this system is transmitted in the form of data blocks, and the data blocks are connected into a chain by appending at the end, hence the name blockchain. From a technical point of view, there are no significant barriers and no innovative progress between blockchain and the IT technology that existed before; but from a value point of view, they are fundamentally different – all previous technologies were designed to Improve efficiency, while blockchain does the opposite.
Since Bitcoin is the iconic existence of the blockchain, we might as well take it as a sample.
Each transaction accounting in the Bitcoin system is verified by countless users throughout the network, and the transaction can only be established after the verification is passed. The first user to successfully book the account can get a certain amount of Bitcoin reward. This information processing process is commonly known as “mining”. At present, the number of active users of the Bitcoin system is about 5 million, and the processing volume in 2017 is about 30 million transactions. What is the size of 30 million transactions? On November 11, 2017, Alipay completed 1.48 billion transactions, which is about 50 times the annual transaction volume of Bitcoin.
This gap doesn’t mean much. After all, the number of users of Bitcoin is much lower than that of Alipay, and the application scenarios are far less than that of Alipay, so it is not surprising that there is an order of magnitude difference in transaction volume. What really explains the problem is the power consumption to support these 30 million transactions: foreign media Digiconomist announced that the power consumption of the Bitcoin system in 2017 reached 30 billion kWh, accounting for 0.13% of global power consumption, more than dozens of countries. national annual electricity consumption. In other words, to process a transaction, the Bitcoin system needs to consume an average of 1,000 kWh of electricity; based on the electricity price of residents in my country, it is equivalent to 3,000 yuan per active user. Such incredible power consumption means huge computing power allocation, which is in sharp contrast to its small processing power.
The inefficiency of “decentralization” is not only reflected in computing power, but also in data storage.
Continuing to take Bitcoin as an example, as we all know, Bitcoin (blockchain technology) requires users to store public ledgers in a distributed manner. The logic behind it is very strange: the concept of “decentralization” believes that the managers of the central ledger will cheat, so the storage of the ledger must be publicized. At present, the size of the complete Bitcoin public ledger has exceeded 150 GB, and is rapidly increasing at a rate of tens of GB per year – just to support 5 million users and 30 million transactions per year. If it were to one day match the processing capacity of current Alipay, the size of the Bitcoin ledger would increase by more than 500TB per year. This is equivalent to backing up the stored data of Alipay servers on all users’ personal computers, and its absurdity is obvious.
To address this, the Bitcoin system now allows users to store incomplete public ledgers, known as “light wallets,” but whose transaction verification still relies on the complete ledgers of others on the network. Let’s imagine that when the public ledger is so large that most people cannot store it completely, wouldn’t the remaining complete user nodes become the central ledger again?
Extend the vision to blockchain applications other than virtual currency (�(if it exists), the public ledger needs to record not only the pure digital transaction amount, but also the insurance information of each car and the credit information of each person. “Centralized” is stored on each user’s terminal, then what we need will be astronomical storage space. In a short time, this will be an impossible problem to solve.
From a philosophical perspective, the essence of science is doubt, and the essence of religion is belief. As a concept in the field of technology, how does blockchain make people ignore many paradoxes and become their believers? The answer is of course inseparable from Bitcoin, the miracle of wealth creation in this world.
Philosophy of Bitcoin
I don’t know since when, the big guys began to deliberately separate Bitcoin and blockchain as two concepts, and they all said that Bitcoin is only one of the applications of blockchain .
The motivations are varied.
Anyone with a little common sense in economics knows that Bitcoin cannot become the currency of normal economies. It has its own deflationary properties, ignores monetary policy, and is inconsistent with modern economic theory. The more important reason is that the credit currency it challenges is too powerful. Except for a few failed countries in the world, all currency is issued based on government credit. The reason why credit currency is also called legal currency is that most countries have clearly stipulated by law that domestic currency is the general equivalent that “must accept” in the domestic circulation field. In this way, the state ensures that the credit currency is not rejected, and at the same time ensures that the rights of the currency holder are not violated. In other words, the credit currency is not issued out of thin air. It is endorsed by the government’s credit behind it and supported by the state machinery.
The issuance mechanism of Bitcoin (that is, mining) is intended to “decentralize” the government’s currency centralization, and behind it is to question the rationality of the existence of the government.
As mentioned earlier, the logical starting point of “decentralization” is the distrust of centralized institutions. The fundamental reason why Bitcoin fundamentalists choose to use “machine consensus” instead of “system consensus” is that the government-led currency issuance system cannot reflect fairness and justice – inflation, inequality of wealth – these bitcoins are trying to solve The problems all point to the establishment. From this perspective, the inefficient consensus mechanism of Bitcoin also has the philosophical meaning of “efficiency for fairness”.
If technological progress will eventually make the lost efficiency negligible, does that mean that “untrustworthy” centralized institutions do not need to exist?
This is a dangerous question, and fortunately we don’t have to answer it for now—because Bitcoin’s attempts at “fairness” have largely failed.
The original intention of the Bitcoin designers was to hope that Bitcoin participants would have roughly equal opportunities to obtain Bitcoin during the same period. To this end, a rather sophisticated and idealized blockchain algorithm is designed, which is the so-called PoW (Proof of Work) mechanism. By exhausting random number variables, the first user who obtains the specific required hash function value (Hash) will have the right to book the round of transactions and receive the corresponding Bitcoin reward. Based on the PoW mechanism, the probability that each user obtains Bitcoin is directly determined by the computing power he contributes. The more investment, the greater the return, which seems reasonable and reasonable.
Of course, things are not that simple.
On the one hand, Bitcoin’s PoW is extremely energy-intensive, and the expected probability of obtaining a specific required hash value every time a random number is generated is 1/62^18 (less than one in a billion billion billion), so The entire equipment needs a large number of exhaustive operations to determine the accounting right. Bitcoin’s high operating costs are largely due to this “fair” incentive mechanism.
On the other hand, Bitcoin designers made a serious misjudgment about the distribution of computing power. He originally thought that users would honestly use the CPU to run the mining program, but limited by the number of CPU cores and cost, a single user is unlikely to concentrate too much computing power. However, what happened later has been understood by everyone. From GPUs to mining machines to large mining pits, a system aimed at decentralization has become almost oligarchic.
The reason why Bitcoin deviates significantly from its concept is not accidental.
Large-scale production has brought many benefits to “mining giants”: stronger bargaining power for electricity bills, higher utilization efficiency of fixed assets, lower comprehensive labor costs, and thinner R&D amortization costs. Even for virtual products like Bitcoin, the production process still conforms to the simple economic law of diminishing marginal cost, which is the inevitability of centralization. From the point of view of natural science, similar conclusions are also established: an individual with a scattered sand is the state with the highest entropy value, and high entropy means incompetence.
Some people believe that PoW distorts the concept of Bitcoin, reduces efficiency, and induces competition for computing power.�� Solution. So they designed new incentive mechanisms such as PoS and DPoS. In my humble opinion, these efforts will not bear fruit, because on the seesaw of “efficiency” and “fairness”, you can’t satisfy everyone, or even most people.
To put it a little more mysteriously: any kind of virtual currency incentive mechanism is a set of economic system – “dead system” cannot guarantee the stable operation of a dynamic economic system, only “living people” can.
The dilemma of de-tokenization
Due to the various problems of Bitcoin, people of insight in the circle realized that if they continue to bind the blockchain and Bitcoin together, they will lose both. Cutting ties in the name of “technological innocence” is a top priority. This is not only in response to the current situation, but also a wish: the influence of Bitcoin has been too far-reaching, if the blockchain is not liberated, the space for latecomers to become rich will be squeezed out.
However, is it really possible to demonetize the blockchain?
Many ordinary people who do not know the truth, and even some well-known investors feel that the “real, tamper-resistant” blockchain has infinite value just by virtue of the technology itself.
I have to say that this is a huge misunderstanding.
For example, inter-bank settlement, even if the blockchain system successfully completes the bookkeeping operation, but a rogue bank refuses to make payments to the outside world, can the blockchain replace the law and ensure that the rights of the counterparty bank are not infringed? Another example is product anti-counterfeiting. Even if the QR code is correct throughout the whole process, the seller will put the defective product in the box for the first time. Can the blockchain work magic so that customers can receive the genuine product smoothly? In fact, the “real and tamper-proof” of the blockchain can only act on virtual information at best, and its tentacles cannot reach the real world at all.
Now, however, these concepts are being misused, intentionally or not. Speaking responsibly, most of the promising blockchain applications are completely based on the literal meaning of “true and untamable”. The people who propose these applications do not understand the blockchain technology itself. It’s just application scenarios where “authenticity” is a pain point – and such scenarios are of course ubiquitous. However, in the end, everyone will find that even if many difficulties such as inefficient redundant security are overcome, the imagined blockchain needs will still not arise.
Because this is largely not a technical problem, but an economic one.
The “decentralized” design of the blockchain means that the operating cost of the system will be allocated to each user, but the nature of rational people has never been sharing and dedication, but free riding. Take Bitcoin as an example, not to mention hardware investment such as mining machines, only electricity bills, and the average active user will pay 3,000 yuan per year. If the blockchain application does not generate tangible individual benefits, there will be no spontaneous participants, and even if they reluctantly participate, its reliability will be questioned. Therefore, the commercial application of blockchain cannot be decoupled from the incentive mechanism.
To put it more in-depth, the consensus of the blockchain is not only the consensus on the technical public ledger, but also the consensus on the value medium of the blockchain. For example, in the Bitcoin system, if there is no incentive mechanism, or if Bitcoin is worthless, no one will provide computing power, no one will provide storage space, and no one will preach preaching – Bitcoin itself is a system Values, ideas and technologies are just beautiful stories.
The various blockchain applications reported by the media can be summed up in two ways: either they use the subject matter to hype and force the application of blockchain algorithms in the transactions of centralized institutions; Regardless of how and how difficult it is to implement. For some reason, these media have reached a wonderful tacit understanding in the process of advocating blockchain, and never mention virtual currency, which has seriously misled everyone into thinking that blockchain is just a pure network technology. In fact, if a veritable blockchain ecosystem does emerge, then the last thing the white paper sees is virtual currency.
According to this, we may wish to re-examine the relationship between virtual currency and blockchain.
There is a saying in the circle that “blockchain is the foundation, virtual currency is used”, and the authenticity of this statement is very difficult to distinguish.
It is clarified that the essence of blockchain is a specific algorithm created by virtual currency to establish a “fair incentive mechanism”. The so-called “blockchain-based, virtual currency for use” is tantamount to buying money back . Here we can assert that once the soul of virtual currency is lost, the blockchain has no value.
This argument may be difficult to accept for a while, but there is nothing wrong with the logic.
The so-called “value generation” is nothing more than three criteria: creating demand, reducing costs, and reshaping fairness. From the perspective of cost, blockchain has no advantage over centralization; from the perspective of fairness, the grand social experiment of Bitcoin has already been revealed. So the only suspense left is whether the blockchain “creates demand”.
�At that time, people in the currency circle can jump out and say categorically, of course there is demand, look at this surging ICO!
ICO carnival
ICO, the full name of InitialCoinOffering, is the initial coin offering. In short, it is a crowdfunding financing behavior in which the specific virtual currency of the early project is priced in a common virtual currency such as Bitcoin, and the shares are sold to the public. How early are the so-called “early projects”? It is enough to form a team and write a white paper. If you have spare time, doing a PPT by the way is quite diligent. As for due diligence and financial analysis, they are completely unnecessary, because most projects have no operating income.
The title of “specific virtual currency” is a little unprofessional. The popular name in the currency circle should be token, and the elegant translation is “token”. In the white paper, the project team will draw a variety of pie, telling you how much “value” the home pass will have. But if you want to know what a token is, I’m sorry, there is a fine tradition in the blockchain circle, called “unspecified language”.
For some meaningful reasons, most ICO legal documents (LegalDocuments) are in pure English, and the real definition of the token is actually hidden in it. Almost all ICOs have provisions similar to the following in their legal documents: “The token does not confer any rights other than the returns specified in the white paper, and will only take effect when the project is successful. Crowdfunding investors cannot exercise control over project development and management. The token does not mean that investors have any form of ownership of the project, nor can they obtain future income and intellectual property related to the project.”
This jaw-dropping text is, to put it bluntly: although You give money, but you are nothing. ICO crowdfunding is not the kind of crowdfunding we know in the past. What investors buy with money is not shares, but chips. When the dealer stops playing, the chips are classified as air — not to mention that most dealers can’t play at all. stand up.
Without underlying assets, no subject credit, no business model, and no legal protection, can such a virtual currency be sold? The answer turned out to be yes.
It all seems ridiculous, but the logic behind it is actually very simple: because a lot of people make money through ICOs.
Writing a white paper by the construction team is the first link of the ICO industry chain. Next, it will pull the platform of the big guy and issue coins on overseas “exchanges”. When the virtual currency is launched, it will also manipulate the currency price to attract more speculators to enter the market. In the end, when you see the right time, you can cash out and leave the field even if you have finished the whole journey. Some people have achieved financial freedom directly in this game; some have not eaten meat, but also drank soup.
In the face of the miracle of making wealth with such a low threshold, anyone should be moved.
However, if the project itself is not profitable, no matter how it is packaged and beautified, ICO is still a zero-sum game after all – if someone makes a lot of money, then someone must lose their bottoms. This is like the MLM we know well, everyone knows that taking the last hit will kill them, but they all feel that they will not receive the last hit.
What role does the blockchain play in the ICO tide?
As we all know, decentralization, de-crediting and fairness and justice are the concepts advertised by the blockchain. We look at ICO on the other hand: if you want to launch coins, you must pay a huge “listing fee” to a centralized exchange. How “decentralized” is this? The project team is prone to fraud, the currency circle media is deliberately misleading, and the trading account is frequently hacked. What kind of “de-credit” is this? Bankers and predators wantonly drive up prices, make huge profits, and squeeze leeks. How “fair and just” is this? In fact, apart from offering virtual currency and gimmicks, blockchain is nothing in the currency circle. The irony is that many of the virtual coins issued by ICOs are not even based on blockchain technology.
So, ICO is not the demand created by the blockchain, but the shame of the blockchain.
The future of chains and coins
Since we already know that virtual currency is the only value of the existence of the blockchain, we have a general idea for the future analysis of the blockchain.
At the moment when legal currency is fully electronic, virtual currency based on blockchain technology does not have much practical value in normal social life. However, in special scenarios, virtual currency has an advantage that cannot be copied by electronic legal currency, that is, privacy.
Any transaction that uses a bank as a payment channel can be regulated. If the authorities want to, they can know who you gave the money to, the background of the transaction, when it happened, and everything. So before Bitcoin, the vast majority of shady transactions were done in cash. You’ve only seen gangster movies with a big box of cash to buy drugs, never seen one with a POS machine.
The advent of Bitcoin revolutionized money laundering, drug trafficking, and black market arms sales. With this completely anonymous currency, criminals no longer have to pay for a boxBoxes of cash are intimidating, and you’ll never have to pay a trade-in for double-digit dollars—Bitcoin is portable gold, as it’s designed to be.
So, Bitcoin and its alternatives are unlikely to be wiped out, as the need to escape regulation will always exist.
As long as the virtual currency is immortal, the blockchain economy must have room for survival, because the value represented by the virtual currency must need a way to cash, and this way cannot always be legal currency.
I want to insert a sentence here. Recently, the compromised products of blockchain and centralized ledgers, such as Raiden Network, are gradually emerging. In principle, the central ledger can greatly improve processing efficiency and adapt to large-scale and high-frequency applications. However, if the main appeal of virtual currency core users is to get rid of supervision, then this function may not be popular. The result will be known soon.
Another question that everyone is concerned about is: Will the surging ICO lead to the explosion of virtual currency? The answer is of course no.
Virtual currency is not protected by law, so its public acceptance largely determines its value and future. When accepting fiat currency payment, we default to the fiat currency we get, and others will also accept it. Its face value does not generate any discount during the circulation process, and it has 100% liquidity. The situation in the case of virtual currency is different. Due to the lack of quantitative indicators of liquidity, we can only decide whether to accept this kind of virtual currency payment based on the general judgment of the public on its acceptance. This way of judging creates a powerful Matthew effect, as public choices converge rapidly.
On the other hand, there is also an upper limit on the types of currencies that the public can spontaneously accept. Taking shared bicycles as an example, we will deposit a deposit for Mobike, OFO, and Bluegogo for those with a big heart. How many people have deposited more than 4 types of shared bicycles at the same time? Under normal circumstances, the public’s acceptance limit for homogenization functions is only “three”. In the case of currency, the first position of fiat currency cannot be shaken, the second most likely is Bitcoin, and the third is Ethereum – so unfortunately, all other virtual currencies do not grow much.
Some people will say that this is based on the judgment of the public chain, and we also have a private chain and a consortium chain.
Here, we have to take a clear stand: a private chain is a central ledger, and has nothing to do with the concept of blockchain. As for the alliance chain, there are more related misunderstandings. For example, many consortium chains are now conceived without a token component, which is the biggest misunderstanding. As analyzed earlier, if there is no incentive mechanism, high-frequency applications will become a free-rider tool for low-frequency applications, and even worse, the medium for value transmission will be missing. In addition, if there are differences in how the token value is redeemed between different applications, arbitrage within the alliance will also be inevitable. In short, compared with the public chain, the consortium chain has only a few more problems except for the slight improvement of privacy. The gap in the universality of Token means that it can only survive on the value of the underlying assets in the shadow of the public chain.
To sum up, we also have a basic understanding of the application scope of the future blockchain: most of the naturally growing blockchain economies will exist based on Bitcoin and Ethereum. The natural growth mentioned here specifically refers to the distinction from pseudo-blockchains that are forcibly affiliated with centralized institutions. Whether it is inter-bank settlement, product anti-counterfeiting or any other scenario, if the consensus and trust among the participating entities already exists, the so-called blockchain application is at best a database, and it will not be an optimally designed database.
The last question: When will the blockchain craze fade?
This is a difficult question to answer. But there is a good saying: You can fool everyone at one time, and you can fool one person forever, but you can’t fool everyone all the time.

❼ Can blockchain technology ensure that the privacy of enterprises or individuals will not be violated and leaked?

Jinwowo Network believes that privacy protection is the advantage of blockchain. Comprehensive use of cryptography, distributed structure and other technical means to protect privacy.
Jinwowo will use blockchain technology to promote the legalization of big data commercialization. The encryption of blockchain technology can ensure that the privacy of data sources can be better protected while calling big data.

❽ How to ensure the security of blockchain use?

Blockchain itself solves the problem of large-scale collaboration between strangers, that is, strangers do not need to trust each other can cooperate with each other. So how to ensure the trust between strangers to achieve mutual consensus mechanism? The centralized system uses a trusted third-party endorsement, such as a bank, which is a reliable and trustworthy institution in the eyes of the common people. The common people can trust the bank, and the bank will solve the real disputes. But how does a decentralized blockchain guarantee trust?
ActualAbove, the 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 will only introduce the basic knowledge of cryptography related to blockchain, including Hash algorithm, encryption algorithm, information digest and digital signature, zero-knowledge proof, quantum cryptography, etc. You can use this lesson to understand how the blockchain under cryptography guarantees its confidentiality, integrity, authentication and non-repudiation.
Basic Course Seventh Lesson: Basic Knowledge of Blockchain Security
1. Hash algorithm (Hash algorithm)
Hash function (Hash), also known as hash function. Hash function: Hash (original information) = digest information, the hash function can map a binary plaintext string of any length into a shorter (usually 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 output of abstract information.
2. Input sensitivity: Even if the plaintext input has any slightest change, the newly generated summary information will change greatly, which is hugely different from the original output.
3. Easy to verify: both the plaintext input and the hash algorithm are public, and anyone can calculate whether the output hash value is correct.
4. Irreversible: If there is only the output hash value, it is absolutely impossible to deduce the plaintext by the hash algorithm.
5. Collision avoidance: It is difficult to find two pieces of plaintext with different contents, but their Hash values ​​are the same (collision).
Example:
Hash (Zhang San lent Li Si 100,000 for a loan period of 6 months) = 123456789012
A record of 123456789012 is recorded in the ledger.
It can be seen that the hash function has 4 functions:
Simplified information
It is well understood, the information after hashing becomes shorter.
Identification information
123456789012 can be used to identify the original information, and the summary information is also called the id of the original information.
Hidden information
The ledger is a record of 123456789012, and the original information is hidden.
Verification information
If Li Si deceived during repayment that Zhang San only lent Li Si 50,000, both parties can use the hash value and the previously recorded hash value of 123456789012 to verify the original information
Hash (Zhang San lent Li Si 50,000 yuan for a loan period of 6 months)=987654321098
987654321098 is completely different from 123456789012, which proves that Li Si lied, and successfully guarantees that the information cannot be tampered with .
Common Hash algorithms include MD4, MD5, and SHA series algorithms. Now, the SHA series algorithms are basically used in mainstream fields. SHA (Secure Hash Algorithm) is not an algorithm, but a set of hash algorithms. It was originally the SHA-1 series, and now the mainstream applications are SHA-224, SHA-256, SHA-384, SHA-512 algorithms (commonly known as SHA-2), and recently SHA-3 related algorithms have also been proposed, such as those used by Ethereum The KECCAK-256 belongs to this algorithm.
MD5 is a very classic Hash algorithm, but unfortunately both it and the SHA-1 algorithm have been cracked. It is considered by the industry that its security is not enough to be used in commercial scenarios. Generally, at least SHA2-256 or more is recommended. Safe algorithm.
Hash algorithms are widely used in blockchains. For example, in a block, the next block will contain the hash value of the previous block, and the content of the next block + the value of the previous block. The hash value jointly calculates the hash value of the next block, which ensures the continuity and immutability of the chain.
Second, Encryption and Decryption Algorithms
Encryption and decryption algorithms are the core technologies of cryptography, which can be divided into two basic types in terms of design concepts: symmetric encryption algorithms and asymmetric encryption algorithms. According to whether the keys used in the encryption and decryption process are the same, the two modes are suitable for different needs and just form a complementary relationship. Sometimes they can also be used in combination to form a hybrid encryption mechanism.
Symmetric cryptography (also known as public key encryption, common-key cryptography), the encryption and decryption keys are the same, its advantages are high computational efficiency and high encryption strength; its disadvantage is that it needs to be advanced in advance Shared keys are easy to leak and lose keys. Common algorithms are DES, 3DES, AES, etc.
Asymmetric cryptography (also known as public key encryption, public-key cryptography), which is different from the encryption and decryption keys, has the advantage that it does not need to share keys in advance; Only short content can be encrypted. Common algorithms include RSA, SM2, ElGamal and elliptic curve series algorithms. Symmetric encryption algorithm, suitable for the encryption and decryption process of a large amount of data; cannot be used for signature scenarios: and it is often necessary to distribute keys in advance. Asymmetric encryption algorithms are generally suitable for signature scenarios or key agreement, but are not suitable for encryption and decryption of large amounts of data.
Third, message digest and digital signature
As the name suggests, message digest is a�� performs a Hash operation to obtain a unique digest value to replace the original complete information content. Information digest is one of the most important uses of the Hash algorithm. Using the anti-collision feature of the Hash function, the information digest can solve the problem that the content has not been tampered with.
Digital signature is similar to signing a 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 at the same time confirm the source (or non-repudiation) .
We have two feature requirements for digital signatures that align with our expectations for handwritten signatures. First, only you can make your own signature, but anyone who sees it can verify its validity; second, we want the signature to only be related to a specific document and not support other documents. All of these can be digitally signed through our asymmetric encryption algorithm above.
In practice, we generally sign the hash value of the information, rather than the information itself, which is determined by the efficiency of the asymmetric encryption algorithm. Corresponding to the blockchain, the hash pointer is signed. In this way, the entire structure is in front, not just the hash pointer itself.
Fourth, zero knowledge proof (Zero Knowledge proof)
Zero knowledge proof means that the prover makes the verifier believe that a certain assertion is correct without providing any additional information to the verifier.
Zero-knowledge proof generally satisfies three conditions:
1. Completeness: a true proof can allow the verifier to successfully verify;
2. Soundness: a false proof The verifier cannot be verified;
3. Zero-Knowledge: If it is proved, no information other than the proof information can be obtained from the proof process.
V. Quantum cryptography
As the research on quantum computing and quantum communication attracts more and more attention, quantum cryptography will have a huge impact on the security of cryptographic information in the future.
The core principle of quantum computing is to use qubits to be in multiple coherent superposition states at the same time. In theory, a small number of qubits can express a large amount of information and process it at the same time, which greatly improves the computing speed.
In this case, 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 only in the theoretical stage, and there is still a long way to go before large-scale commercial use. However, the new generation of encryption algorithms must take into account the possibility of this situation.

❾ What should I do if the private key of the unique proof of blockchain identity is lost

What does it mean? If it refers to the private key of the Bitcoin blockchain, it cannot be found. The private key itself is a randomly calculated string, and the wallet address can only be derived from the private key, not the other way around.

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