Blockchain world standard
1. When Honran police rushed into Mariana Catalina Izaguirre's home one day in 2009 and wanted to expel her, she had lived in this shabby house for more than 30 years. Unlike her neighbor, Mariana Catalina Izaguirre even has a government housing certificate, but unfortunately, according to the information from the local government housing authority, the housing department and another person, the "homeowner", applied to the court for an expulsion order, and finally Ms. lzaguirre was forced to leave
this kind of wrangling is very common all over the world e to unclear registration or missing records. The lack of housing ownership protection is also the source of injustice. It has also become difficult to use houses or land as collateral for financing
bitcoin can make such problems disappear. Bitcoin is a "smart" currency based on encryption algorithm. We should pay more attention to the technology behind bitcoin: blockchain. It means more than money or cash. It creates a way of accounting to solve mutual distrust
that's why politicians consulted Factom, an American start-up that provides a prototype for land registration based on regional chains, to clean up Honran property institutions. Greece is also interested. It has no proper land registration policy. Only 7% of the land is right on the map
2. Blockchain and other similar "distributed account book" applications can be extended to prevent diamond theft and supermarket pipeline. NASDAQ Exchange will soon use blockchain system to record transactions of private enterprises. British banks dislike technological civilization, but it seems to be stimulated: in its research report last year, it wrote that distributed accounting is a great innovation and will have a profound impact on the financial instry
politicians think further: when partners and the left gathered in this year's ouishare Fest in Paris to discuss how grassroots enterprises have shaken big data companies such as Facebook, the regional chain appeared in every speech. In the dream of freedom in the world, more government regulations are replaced by private contracts between indivials - encryption algorithms will strengthen themselves
the blockchain was conceived by Satoshi Nakamoto, the amazing and so far the only confirmed founder of bitcoin - "completely equivalent electronic currency," he wrote in an article published in 2008. In order for it to be like money, bitcoin has to be transferred from the account it is fighting for, and can be consumed twice by the same person. In order to realize the dream of a decentralized system like Nakamoto, bitcoin must avoid any dependence on third parties, such as banks hidden behind ordinary payment systems
blockchain can replace the third party. It can hold the transaction history of each bitcoin and provide evidence of any person at any time. Distribution systems can be replicated in thousands of computers - the "nodes" of bitcoin - everywhere in the world, and can be made public. But even with such openness, it is still credible and safe. The complexity of the mathematical algorithm and the computational brute force cracking built in its "consensus mechanism" - the node agrees to upgrade the blockchain process according to the bitcoin circulation - ensure this
for example, Alice wants to pay Bob for rental services. They all have bitcoin wallets - software that goes directly to the blockchain, not to the web like a browser, but doesn't identify users in the system. When Alice's wallet began to apply, the transaction started, and the blockchain began to change to show that Alice's wallet was less and Bob's was more
the network needs to change through several stages in this process. When the application passes through multiple nodes in the network, check the ledger to confirm whether Alice has the bitcoin she wants to spend. If everything looks ok, the specific node will instruct miners to bundle Alice's request to connect with other similar reputable transactions, and create a new mole in the blockchain
this involves decomposing the mole into a series of data of specified length by encrypting a hash function (see chart). Like many encryptions, this hash is a one-way street. Data can be dispersed, but conversely, it is impossible to aggregate data from dispersion. But even though hash doesn't hold data, it's still unique. Changing the entry mole in any way - changing the transaction with a simple number - hashing will be different
3. Along with other data, hash will be placed in the first place (header) of the development mole. The first one then becomes the basis of practical mathematical puzzles, again involving hash functions. Puzzles can only be solved by tests and errors. Through the Internet, miners is experimenting with hundreds of millions of possibilities to find answers. When a miner finally finds out the answer, other nodes will quickly check (go one-way again: it's hard to solve, but it's easy to check), and each node will confirm the solution, and then upgrade to the blockchain. The first hash will be the confirmation line for the new mole, which is now part of the account book. Alice pays Bob and all other transactions in the mole are confirmed
in the decryption phase, three things are introced to greatly enhance the security of bitcoin. One is chance. You can't predict which miner will solve the puzzle, so you can't predict who will upgrade the blockchain at a given time, except that it must be the most diligent miner, not other random slackers. It makes cheating difficult
the second point is history. Each new first part contains the hash function of the first part of the previous mole, and it contains the hash function of the last part, so it goes back and forth to the starting point. This association makes the mole a circular chain. Starting with all the data in the account book, it's a small matter to regenerate the top of the latest mole. Despite making a change anywhere - even back to one of the earliest moles - the first changed mole will be different. This means the same for the next mole, and all the later moles. The account book will not pass through the latest mole identifier and will be rejected
is there a solution? Imagine Alice changing her mind to pay Bob and trying to rewrite history so that bitcoin will still be in her purse. If she is a capable miner, she can solve the urgent puzzle and make a new version of blockchain. But in the time she does, the rest of the network will have extended the original blockchain. Nodes will always work in the longest version of the blockchain. This rule prevented two miners from finding a solution at the same time and led to worse consequences in the chain than temporary forks. It also prevents cheating. In order for the system to accept her new version, Alice needs to extend it faster than anyone else. Not being able to control more than half of the computers - the technical term is "51% attack" - should not be possible
4, not to mention the possibility of subverting the above network, another deep-seated question is: why do you want to be a member of this network? The answer is the third "decryption" step, and there are rewards. Each new block has a new bitcoin, and the person who solves the puzzle will get 25 bitcoin rewards, about $7500
all the above ingenious designs are not the real attraction of bitcoin. Its value lies in instability and unpredictability, as shown in the figure below, but the total amount of bitcoin is fixed. The mechanism of blockchain also works well. According to a website called blockchain.info, on average, more than 120000 transactions are added to the blockchain every day, which means about $75 million in transactions. At present, there are 380000 blocks, and the size of this account book is nearly 45gb
most of the data in the blockchain is bitcoin, but it is not necessary. Mr Nakamoto has also created a distributed system and written a related explanation. Technology geeks call it: open platform. This platform imitates the Internet, including operating systems such as Android or windows. Developers can develop applications based on the basic functions of blockchain without anyone's permission. Chris Dixon of Andreessen Horowitz, which invests in bitcoin startups, said: this kind of network will eventually become a public database. It is understood that Andreessen Horowitz has invested in coinbase, a bitcoin wallet company, and 21, a bitcoin hardware equipment company for the public
at present, the application based on blockchain has three major fields. The first is to complete all suggestions through blockchain. Colo, a start-up company, is betting that in this model, they have developed an algorithm to "Polish" some small bitcoin transactions, so that they can represent such transactions as securities and precious metals
to protect the validity of land or house signature has become a typical application in the second category. Bitcoin transactions will add the signature to the account book of the blockchain. Everledger, a start-up company, protects luxury goods in this way. For example, they record the texture attribute of a gem in the blockchain data. If the gem is lost, it can provide the most intuitive proof. Onename stores personal information in a similar way; Note that this kind of application is not pure bitcoin transaction, so you need to give more trust first. For example, you need to tell the application developer some accurate information about yourself
the third kind of application has greater ambition, and "smart contract" can automatically detect whether there are various environments in which it can take effect. This is because bitcoin can be programmed so that it can be available or unavailable in special situations
lighthouse, founded by Mike Hearn, a well-known bitcoin engineer, is a decentralized crowdsourcing project. If enough money goes into the project, then everything starts. If the goal is not reached, it stops. Heran believes that his project can be cheaper and more independent than those of his friends who use bitcoin
5. According to Albert Wenger of USV, a New York venture capital company, the emergence of distributed ledgers has opened up an almost new quadrant of possibilities. This company has invested in a number of decentralized companies, such as openbazaar, which provides P2P transactions. In addition to cheering for the blockchain, some people question its security and scalability. Blockchain is very suitable for bitcoin, but in some niche applications, it can't support the use of millions of users
although Nakamoto's blockchain design has proved to be invincible so far, academic research also believes that it is almost impossible to do bad things on the blockchain without controlling 51% of the whole blockchain. In the past, bitcoin players were limited to a small circle. Today, bitcoin mining is controlled by various big bitcoin pools, where small miners share their efforts and get rewards
another concern is the environment. In order to get more bitcoin, the miners are more interested in computing power
(1) distributed ledger, that is, transaction bookkeeping is completed by multiple nodes distributed in different places, and each node records complete accounts, so they can participate in monitoring the legitimacy of transactions, At the same time, they can testify together
different from traditional distributed storage, the uniqueness of distributed storage of blockchain is mainly reflected in two aspects: one is that each node of blockchain stores complete data according to block chain structure, while traditional distributed storage generally stores data in multiple copies according to certain rules. Second, the storage of each node in the blockchain is independent and has the same status, which relies on the consensus mechanism to ensure the consistency of storage, while the traditional distributed storage generally synchronizes data from the central node to other backup nodes[ 8]
no single node can record the account data separately, so as to avoid the possibility that a single bookkeeper is controlled or bribed to record false accounts. In theory, unless all the nodes are destroyed, the accounts will not be lost, so as to ensure the security of the account data
(2) asymmetric encryption and authorization technology, the transaction information stored on the blockchain is public, but the account identity information is highly encrypted, which can only be accessed under the authorization of the data owner, thus ensuring the data security and personal privacy
(3) consensus mechanism is how to reach a consensus among all accounting nodes to determine the validity of a record, which is not only a means of identification, but also a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and achieve a balance between efficiency and security
the consensus mechanism of blockchain has the characteristics of "the minority is subordinate to the majority" and "everyone is equal", in which "the minority is subordinate to the majority" does not completely refer to the number of nodes, but also can be the computing power, the number of shares or other characteristics that can be compared by computers“ "Everyone is equal" means that when the nodes meet the conditions, all nodes have the right to put forward the consensus results first, and then directly recognized by other nodes, and finally may become the final consensus results. Taking bitcoin as an example, the workload proof is adopted. Only when more than 51% of the accounting nodes in the whole network are controlled can a nonexistent record be forged. When there are enough nodes in the blockchain, this is basically impossible, thus eliminating the possibility of fraud.
(4) smart contract, which is based on these trusted and tamperable data, can automatically execute some pre-defined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and reliable, it is easy to carry out automatic claim settlement in some standardized insurance procts
China has started to establish a national standard for blockchain to promote the construction of blockchain standard system from top-level design, which is expected to be completed by the end of 2019 at the earliest
in this regard, Zhao Wu, founder of Beijing Huashun Xin'an Technology Co., Ltd., also said that although the blockchain has disruptive technology potential, we must realize that the blockchain is still in its infancy, far from reaching the stage of subverting the world
Yu Kequn stressed that the independent and controllable blockchain network is intended not to be controlled by others technically, but also to promote the healthy development of blockchain. Security is the future life of blockchain. Only its own security can make blockchain technology landing. This requires us to pay equal attention to the development of blockchain technology and its security attributes, even ahead of timein this regard, Li Ming also said that an important part of the standard is the information security standard, which can also see the importance of security to blockchain technology. He also pointed out that the development of blockchain standards does not mean that it will rapidly promote the development of the instry, but give the instry certain guidance. Previously, China has suffered a lot in terms of international intellectual property rights and standards. In terms of blockchain, China has formed more than 200 patents in terms of international blockchain, and even stands in the forefront of world technology. Therefore, we also need to firmly grasp our right to speak
content source: Xinhuanet
A few days ago, some experts said that blockchain is like the Internet in 1992. The standardization has not been completed yet, and the application and promotion will be limited. It is in the early stage of technology reserve. Once there are standards, all kinds of technology research and development can go on
at present, one of the priorities of China Internet Finance Association in 2018 is to actively promote the standardization construction, "blockchain should have a new technical standard system, especially the establishment of an authoritative third-party certification system, which is the top priority for the development of blockchain finance"
although at present, the regulators are quite concerned about the blockchain, they are mainly concentrated in the financial field, especially in the second half of last year when they took strict control measures on virtual currency and ICO (initial currency issue). From the development of the whole instry of blockchain, the law and regulation are still relatively backward. Compared with overseas advanced countries, there is a lack of special laws to define blockchain and manage its trading and trading platform
I hope the standard of blockchain can be improved as soon as possible
content source: bit110 network
What is a timestamp? Time stamp is a complete and verifiable data that can represent the existence of a data at a specific time point. So what's the use of timestamps
function of time stamp
the client is making a request to the server interface. If the request information is encrypted and intercepted by a third party, the request packet can be used for repeated request operation. If the server does not carry out anti replay attack, the server pressure will increase, and the use of timestamp can solve this problem
tamper proof: the common way to use is to splice parameters, the current project appkey, the "key" agreed by both parties, and add them to the dictionary dictionary set, sort them according to ABCD order, and finally encrypt them in MD5 +. The client sends the encrypted string and request parameters to the server together. After splicing and encrypting according to the above rules, the server compares whether it is equal to the incoming encrypted string
anti multiplexing: encryption in the above way can not solve the problem of anti multiplexing. At this time, it is necessary to generate UTC timestamps on the client and the server respectively. This UTC is to prevent your client and the server from not being in the same time zone, hehe, Then the timestamp can be spelled in the ciphertext, as for the effectiveness of anti reuse. Time stamp technology web link