Is IPv6 a blockchain network
blockchain (English: blockchain or block chain) is a kind of distributed database . You may have heard about bitcoin, which is the core technology. Blockchain is a series of data blocks generated by cryptography. Each data block contains the information of a network transaction, which is used to verify the validity of the information and generate the next block. In a popular concept, blockchain is an account that everyone can keep. In a company or organization, most people only have the right to keep accounts, while only a few people with professional training have the right to keep accounts. Of course, blockchain is not an account book in the traditional sense. It has the following three key points in technical principle: first, decentralization. In a network practicing blockchain technology, each computer covered by it can read and add records. From the perspective of account book, they are the people who keep accounts together, and there is no authoritative person to guide and correct them. Second, asymmetric encryption. Although everyone can remember this account, they will not be able to read it unless they are in the Bureau. Because, in the accounting process, everyone follows the unified encryption rules, but when reading, they must use their own unique decryption method. Therefore, although everyone keeps this constantly updated account, the part they can read is only the one they can decrypt, that is, the part related to themselves. Third, time stamp. That is, time stamp (English: timestamp), refers to the string or coded information used to identify the recorded time and date. Each block on the blockchain is arranged in sequence according to the time it is generated, and is confirmed by collective authentication. Moreover, previous records cannot be modified. Just like in an account, we can index and verify the previous content through the records after a point in time. Once these contents are confirmed, it will be more difficult to tamper with them
blockchain technology is to maintain a growing distributed database of data records. These data are associated with all the data written before through cryptography technology, which makes it difficult for the third party or even the owner of the node to tamper with. Block contains the data that need to be saved in the database, and these data are written into the database through block organization. Chain usually refers to the use of Merkle tree and other methods to check whether all the current blocks have been modified. This is familiar to code farmers who have used git for a long time. Recall how to modify git's history
blockchain technology is mainly divided into three categories, which are open, collaborative and private
public blockchain
example: bitcoin, Ethereum frontier. The data on the public blockchain can be accessed by all people, and all people can issue transactions waiting to be written into the blockchain. Participants in the consensus process (corresponding to the miners in bitcoin) maintain the security of the database through cryptography technology and built-in economic incentives. Open blockchain is completely distributed
highlights and pain points: the open blockchain is completely distributed and has all the characteristics of bitcoin. However, it needs sufficient cost to maintain the system operation and relies on built-in incentives. At present, only bitcoin in the public blockchain is safe enough. If the algorithm is the same as bitcoin, it will be safe; There are no built-in rewards, but they are not; It's easy to concentrate on the attack of computing power (for example, as long as the raid sweeps goods and a large number of graphics cards), and take jujube pills. The more valuable the data on the open blockchain is, the more important it is to examine its security, transaction cost and system scalability
federated blockchain
example: audit system tried by hyperledger and Deloitte. The nodes participating in the blockchain are selected in advance, and there is likely to be a good network connection between the nodes. Other consensus algorithms without workload proof can be used on such a blockchain. For example, a blockchain has been established among 100 financial institutions, and more than 67 institutions must agree to reach a consensus. The data on such a blockchain can be public or internal to these node participants. Distributed in a partial sense
highlights and pain points: collaborative blockchain can achieve a good connection between nodes, only need a little cost to maintain operation, provide rapid transaction processing and low transaction costs, has good scalability (but the scalability will decline with the increase of nodes), and data can have certain privacy. Developers have the ability to change the protocol under the consensus. There is no problem with bitcoin hard fork, but it also means that everyone can tamper with the data together under the consensus. Collaborative blockchain also means that the application scope of this blockchain will not be too wide, lacking the network propagation effect of bitcoin
private blockchain
example: Eris instries. The participating nodes are only users themselves, and the access and use of data have strict authority management. Most of the blockchain technologies recently announced by some financial institutions for internal use are vague, but they are probably all within this scope
highlights and pain points: private blockchain is actually a confusing term. Such a system is nothing more than a shared database in the traditional sense. Merkle tree and other methods are used to try to show that the data in it is verifiable. There are already mature solutions for such databases, and Merkle tree is only one of many mature solutions. It's easy for these projects to be "like eggs". Because the user has the final say, the data inside can not be changed, and there is not much protection for the third party. Therefore, many private blockchains exist by attaching to bitcoin, such as recording system snapshots to bitcoin regularly
at present, the overall planning and top-level design of the blockchain service network have been completed, and the construction of more than 40 public city nodes in 31 provinces and autonomous regions has been completed. The blockchain service network will be tested internally for half a year. In the future, China UnionPay, together with the state information center, China Mobile and other partners, will actively promote security and function testing, technical architecture optimization, business operation scheme formulation, basic service capacity building, innovative application promotion and other work, and finally realize the commercial operation of the whole system
interested developers can view it on the official website of the blockchain service network.
in the near future, the number of devices in the Internet of things will explode, which may be hundreds of billions or trillions. If such a huge network is still managed in a centralized networking mode, the infrastructure investment and maintenance of the data center should be incalculable
in essence, big data belongs to a small branch of database, so this problem is attributed to the relationship between big data and database. Database is a very old research field in software, Internet and it. From the initial file system to ER model, to the three achievements of traditional database, which are known to all, relational model, transaction processing and query optimization, to the rise of NoSQL database after the popularity of Internet, database technology is constantly developing and changing, Then it also includes semi-structured data processing represented by XML and unstructured data processing such as text and voice
it seems that the relationship between blockchain and database is actually such a relationship. From the evolution process of database technology, we can find that it always comes from how to meet new business requirements and then create new data processing technologies. For example, from the beginning of the file system, why do we need the ER model? It is because with the development of the financial instry, people have further requirements for these fast accounting, high concurrency data writing and access, which leads to the emergence and rapid development of the entity relationship model. Why did NoSQL database appear later? It is because the rapid development of the Internet puts forward higher requirements for updating the database, so in essence we think that the whole Internet is a big database
things are always developing. Of course, after we solve the problem of massive real-time data processing on the Internet through NoSQL database and cloud storage, the next problem must come, that is, how to solve the authenticity and effectiveness of data in a large-scale way
for example, it may be related to our diet, from the problem of food and clothing at the beginning, to the problem of nutrition structure, and then to the problem of food safety that everyone is concerned about. The development of database is the same. When we can solve these problems of data storage and data access through ER entity relationship model and NoSQL database, Next, we need to care about and solve the problem of authenticity and effectiveness
so at this stage, these technologies, represented by blockchain, must be a new starting point and new requirements for the authenticity, validity, unforgeability and tamper resistance of data compared with the current database. We can clearly feel that the trend of database and blockchain integration is actually very close and irresistible, just like the movie just mentioned, the procers of content begin to develop in the direction of virtual reality and augmented reality; From the perspective of database, blockchain is a new way of data organization. We believe that big data and blockchain are integrated.
the term "Internet of things" is mentioned almost every day in today's life. Some data show that in 2017, there were about 8.4 billion intelligent devices connected to the Internet, such as thermostats, cameras, street lamps and other electronic procts. According to foreign McKinsey & company data, this number may reach 25 billion by 2025, and the scale of the whole economy will reach 6 trillion US dollars
are you dazzled by such a huge number? Although the Internet of things technology has been widely used all over the world, its defects are graally highlighted
according to the traditional mode, the data center (server) of the equipment manufacturer often collects the information of all connected devices, which determines that the server needs to have strong operation and storage capacity. Moreover, with the geometric growth of Internet of things equipment, the cost of server maintenance will also increase greatly, which makes it difficult for small and medium-sized enterprises to maintain
at the same time, in terms of communication compatibility, the global Internet of things platforms are lack of a unified language, which is easy to cause communication obstacles between multiple Internet of things devices. This is e to the obvious fragmentation of the Internet of things instry, whether it is smart home, smart home appliances, robots, smart cars, etc., the networks they connect are fragmented and closed. In addition, the status quo of the Internet of things instry is still full of mountains, and their influence is relatively limited, so it is difficult to reach a unified standard in a short time
based on this, the standard chain team, after accumulating the previous experience from the Internet of things, combined with the characteristics of blockchain, proposed the concept of Internet of things
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