Example of blockchain encrypted data
some countries have shown great interest in the blockchain technology of decentralized data management framework to store public data. For example, essentia is developing an e-government project with the Central Union of agricultural procers and forest owners in Finland, The project will apply blockchain technology to enable urban and rural residents in Finland to query various records, fully meet the needs of residents and employers, and improve the employment rate. In addition, the use of this technology can also improve the efficiency of government operation, so that residents can easily query ecation, public records, voting and other information
waste recycling
for example, an intelligent waste management system in China adopts the RFID technology of waltonchain company. Using this blockchain application of waltonchain, it can effectively monitor the waste level, so as to improve the management and operation efficiency and resource optimization
identity recognition
chug, a Swiss city known as "encryption Valley", has developed an identity authentication system with its partner uport by using blockchain technology, through which citizens can participate in online voting and proof of residence
border control
essentia has been in contact with the Dutch government, hoping to use its blockchain technology to establish a set of border inspection system for the Dutch government to check passengers between Amsterdam and London. At present, passengers of Eurostar high-speed rail between the two countries need to undergo border control checks at multiple locations. Essentia is working on a blockchain based solution that will securely store passenger data so that inspection records from the Netherlands can also be reviewed by UK Border agencies. Blockchain technology will ensure that the data has not been tampered with and is verifiable and accurate
health care
as we all know, medical records are very scattered and prone to errors. Inconsistent data processing process will make hospitals and clinics often forced to deal with some incorrect or incomplete patient records. For example, Medrec, a blockchain electronic medical record system developed by MIT, uses blockchain technology to promote data sharing. At the same time, it can also provide authentication and confidentiality services
enterprise management
as enterprise customers of Microsoft azure applications, they can make use of blockchain as a service (baas), which will enable enterprises to access smart contracts and blockchain applications in a secure hosting environment. According to media reports, Google is also developing a proprietary blockchain project to support its cloud based business. And alpha, Google's parent company, is developing a distributed accounting project that third parties will be able to use to store data related to Google's cloud services
medical data
medical centers that digitize patient records do not store data among multiple devices. They usually store data on centralized servers, which has become the main target of hackers. The wannacry attack on NHS hospital in the UK proves this. But in addition, even if the security risk is ignored, there is still the problem of fragmentation. At present, there are more than 50 different electronic medical record systems (EHR) operating in hospitals in different cities around the world, and there are usually dozens of different medical application systems in the same city. These independent systems can't perform interoperation, and the data of patients in each hospital can only be distributed in different data storage centers
in the case of patients' life and death, the lack of reliable medical data contrast and slow operation efficiency will be fatal. Essentia's application framework solves all these problems by using blockchain based system, which will store all clinical data of patients, and can access these data immediately regardless of geographical boundaries. In this system, the patient's medical record privacy can also be protected, and only the authorized medical personnel can access it in a specific period of time
Music Proction
one of the main advantages of blockchain technology is that it eliminates unnecessary middlemen or middlemen. The music instry is a typical example. In this instry, if artists are inefficient, they will get very low remuneration. At this time, a number of blockchain based projects have emerged to seek a fairer trading and business environment for music creators, such as artbit, a former gunshot rose drummer Matt Soren as director
carbon compensation
as a highly instrialized country, China's environmental change is huge. In March 2017, IBM and energy blockchain labs jointly launched the hyperledger fabric blockchain project to discover China's carbon assets, which not only creates a measurable and auditable system for tracking carbon emissions, but also provides a tradable market for companies seeking to offset energy consumption and stimulate green instrial practice
supply chain management
supply chain management is considered to be one of the better cases of applying blockchain, because it is very suitable for the express delivery of such goods from delivery to receipt or the whole process from manufacturer to store. IBM and Wal Mart have jointly launched a blockchain food safety alliance in China. The project is also jointly operated with Jingdong company, aiming to improve food delivery tracking and safety assurance, so as to make it easier to trace food safety issues
facts have proved that China is a mature experimental base for blockchain projects, and it is also the location of the world's first blockchain for agricultural procts (5.180, - 0.25, - 4.60%). Louis Dreyfus Co, a world-famous food trader, has established a blockchain technology project in cooperation with Dutch and French banks. Using this project technology, the transaction settlement is faster than traditional methods in the process of selling soybeans to China
diamond instry
De Beers Group, the world's most famous diamond company, has its own blockchain company and has started operation. Its purpose is to "establish a digital record for every diamond registered on the platform". Considering the origin of diamonds, the ethical standards of origin, and the risk of diamond quality, blockchain technology is a good choice, because every record of it is indelible, and it will ensure that the electronic data of each diamond is as permanent as itself
real estate transactions
currently, Ukraine is the first country to use blockchain technology to promote property transactions. Michael Arlington, the founder of techcrunch, a famous technology website and cryptocurrency player, remotely purchased and resold a real estate in Kiev through the smart contract of Ethereum blockchain. This transaction was completed by propy, a start-up company specializing in blockchain real estate transactions
fisheries
blockchain technology is now being used to support the development of sustainable fisheries. Illegal fishing is a common problem in this instry. The distributed ledger technology of blockchain provides a proof of the capture source, processing and sale mode. This "net to table" supply chain allows inspectors to determine whether the fish caught came from a human rights violation area or from a country affected by economic sanctions
art paintings
similar to diamond trading, the art instry relies on the provenance and authenticity of art works. Although the blockchain cannot identify whether a painting is an original or a fake, it can be used to prove the identity of the previous owner of the painting. In addition, blockchain technology is now also used as a means to obtain works of art. It can make tangible goods easily traded and exchanged anywhere in the world without physical transfer from a secure storage place
public facilities
in Freemantle, Australia, a project dedicated to distributed energy and water system management is using blockchain technology, and solar panels (3.340, - 0.06, - 1.76%) are being used in sunny areas to obtain electricity, which is then used to heat water and provide electricity, All these energy conversion and use information will be recorded in the blockchain data
in Chile, the National Energy Commission has started to use the blockchain technology as the verification of the country's energy use data, and some sensitive data will be stored in the blockchain. The application of this technology can be regarded as a means for the modernization and safe operation of power infrastructure in this South American country
LGBT rights
blockchain can help build a "pink economy" and help LGBT communities fight for their own rights without revealing people's identities. This is an extremely important issue, because crimes of discrimination against homosexual groups often occur, especially in countries notorious for human rights violations, Homosexuality is illegal, or at least not allowed
catastrophe bonds
catastrophe bonds may be the only hope for victims of earthquakes, tsunamis and other natural disasters. Blockchain allows fast and transparent reconciliation between the parties, and can ensure that the system can continue to operate normally even under unmanned operation. Now, blockchain has been successfully used in the settlement mechanism of catastrophe bonds
tourism
local institutions in Hawaii are studying how to use blockchain technology to improve the economy, such as opening bitcoin and other monetary payment means to facilitate tourists' transaction of local goods and services. In this way, the Hawaiian government hopes to attract tourists, especially those from Asia, to spend more money in the local area and improve the economic development of Hawaii
homeland security
in 2016, the US Department of Homeland Security (DHS) announced a project that will use blockchain technology as a means of secure storage and capture of data transmission. DHS uses Factom's blockchain technology to encrypt and store data captured by security cameras and other sensors. The application of this blockchain technology will greatly rece the risk of data leakage. At present, the project is still in progress
maritime transportation
it is self-evident that blockchain is used to record ship transportation data. At present, some local shipping projects have adopted distributed ledger technology. In the maritime logistics instry, blockchain technology can make the inevitable cumbersome management proceres in international trade more transparent and orderly. Maersk, one of the world's largest shippers, is a pioneer in the use of blockchain. Today, Yixing international shipping company Zim has also made follow-up use of blockchain technology.
blockchain is a distributed shared ledger and database, which has the characteristics of decentralization, distributed storage, encryption algorithm, whole process trace, traceability, collective maintenance, openness and transparency
take taking charge of Department funds as an example, the traditional way is to assign a person in the Department to keep accounts and manage the Department funds. This person can directly manipulate the remaining amount or the amount of each use, and make profits from it by taking advantage of his authority. This is the traditional centralized management
and in the blockchain management mode, , everyone in the Department has a fund use book, which is added by relevant personnel, and synchronized to their own book after other personnel check. Each transaction will record the usage time, user, amount and content of funds, and generate corresponding serial number for marking. The serial number of each transaction will be stored together with the usage of the next transaction. Each bookkeeping will be encrypted, and so on. At the same time, the account book of each person in the Department is visible to everyone outside, and anyone can query the use of each fund through the account book
in the management mode of blockchain, multi person synchronous bookkeeping is "decentralized management"
everyone in the department checks and stores it, which is called "consensus mechanism"
everyone records the use of each fund, which is called "distributed storage"
the serial number generated by the detailed usage of each fund is called "hash value"
store the serial number and the usage of the next fund, which is called "whole evidence chain"
everyone's account book is visible to everyone outside, which is called "openness and transparency"
to query the usage of each fund is called "traceability"
if someone wants to tamper with a certain amount of funds, the serial number of the funds will be changed accordingly, and this person needs to tamper with all subsequent account records on the account book and the account book records of all people. However, this can be realized on the premise that it can crack the encryption processing of everyone's every bookkeeping. Moreover, once the system finds that there is an account book different from everyone's, the blockchain will automatically correct the "wrong" account book. This can fully guarantee the originality and non tamperability of blockchain electronic data
kuaishang takes the lead in applying blockchain technology to the voting field nationwide, effectively solving the trust problem of voting data, providing the most real and effective data for the participants, protecting the rights and interests of real voting users, and making blockchain technology "people-friendly", so that the general public can quickly perceive and share the information in the field of life services Enjoy the convenience of blockchain technology
Application of blockchain technology in digital asset registration
Jinzhu digital asset service platform takes the lead in using blockchain technology, which is a global distributed ledger technology with the characteristics of traceability, non tampering and non forgery. The digital assets of the platform come from the standard issuers of digital assets, and the asset value is determined by the open market to avoid overestimation or undervaluation
the application of blockchain technology in the financial instry
ant financial's independent and controllable financial grade commercial blockchain platform has been deployed in multiple social and commercial application scenarios by multiple institutions and countries. Ant blockchain platform supports second level confirmation for transactions, and the consensus mechanism uses efficient parallel consensus algorithm to ensure the high performance of the blockchain platform, Ant blockchain has been applied in many proction level applications, applying leading technologies to people's livelihood, commerce, finance and other fields.
asymmetric encryption algorithm is a function that converts the original plaintext file or data into a series of unreadable ciphertext codes by using an encryption key. The encryption process is irreversible. Only holding the corresponding decryption key can the encrypted information be decrypted into readable plaintext. Encryption enables private data to be transmitted through the public network under the condition of low risk, and protects the data from being stolen and read by the third party
the core advantage of blockchain technology is decentralization, which can realize point-to-point transaction, coordination and cooperation based on decentralized credit in a distributed system without mutual trust by means of data encryption, time stamp, distributed consensus and economic incentive, so as to solve the high cost and low cost of centralized institutions Low efficiency and data storage insecurity provide solutions
the application fields of blockchain include digital currency, token, finance, anti-counterfeiting traceability, privacy protection, supply chain, entertainment, etc. with the popularity of blockchain and bitcoin, many related top domain names have been registered, which has a great impact on the domain name instry.
1.1. Introction
practitioners in the computer instry should be very familiar with the word hash. Hash can realize the mapping of data from one dimension to another, and hash function is usually used to realize this mapping. Generally, y = hash (x) is used in the instry. The hash function can calculate a hash value y by calculating X
hash function characteristics in blockchain:
function parameters are string type
fixed size output
is computationally efficient
collision free means that the conflict probability is small: X= y => hash(x) != Hash (y)
hide the original information: for example, the verification of transactions between nodes in the blockchain only needs to verify the information entropy of the transaction, and does not need to compare the original information. The nodes do not need to transmit the original data of the transaction, only the hash of the transaction, Common algorithms include Sha series and MD5
1.2. Hash is widely used in blockchain. One of them is called hash pointer
hash pointer, which means that the value of the variable is calculated from the actual data and points to the actual data location, That is, it can not only represent the actual data content, but also the storage location of the actual data. The figure below shows the schematic diagram of hash pointer

the details of these two digital assets are as follows
bitcoin (bitcoin: bitcoin) was originally a kind of network virtual currency, which can buy real-life goods. It is characterized by decentralization, anonymity, and can only be used in the digital world. It does not belong to any country or financial institution, and is not subject to geographical restrictions. It can be exchanged anywhere in the world. Therefore, it is used as a money laundering tool by some criminals
the full name of NMC is "new media chain", the Chinese name is media chain, and the former domain name currency (also referred to as NMC) is two completely different currencies. NMC is the circulating currency of three decentralized application platforms: coin call [blockchain information community portal], coin search [blockchain network query tool], ncoin [digital currency exchange]. However, the prices of these two kinds of digital currencies will fluctuate with the market, which can not guarantee a development prospect. If the current price is concerned, bitcoin will be a bit higher.
in order to ensure the data security of users, the blockchain system is implemented through a cryptographic algorithm. Specifically, it is implemented through a public cryptographic algorithm mechanism. We all know how a cryptographic algorithm can have a secret key, and the public secret key algorithm is a pair of (that is, two) secret keys, just like tiger amulet, which are used together. One is called public key, which can be disclosed to others. The private key should be kept by itself. In the blockchain system, the public key is used to identify the identity, and the private key is equivalent to the key to decrypt. But the difference is that a public key is only for a unique private key, that is to say, if you forget the private key, it will not be retrieved for you, In the blockchain system, it will not help you retrieve the private key, so you should keep the private key properly
in the blockchain system structure, the data encrypted with public key must be decrypted with the corresponding private key, while the data encrypted with private key
must be decrypted with the corresponding public key, so the data encrypted with private key (usually called "signature") must be decrypted with the corresponding public key, which can play a great role
for a simple example, if Zhang San wants to send a check to Li Si, how can it be sent? In the past, it would be taken by the bookkeeper, so Zhang San thought of a way. He encrypted the check with Li Si's public key, and then signed his name (signed with his private key). At this time, other people would not use it even if they got the check, because only Li Si had his private key, That is, only Li Si can use this check. This function design is called "script system" in the blockchain system
therefore, the private key encrypted by the blockchain digital signature cannot be decrypted by the original encrypted private key, but must be decrypted by the corresponding public key.