Decentralization of peer to peer network in instant messaging

1. What is "decentralization"

"decentralization" is translated from the English word decentralization, which is composed of the prefix de -, stem central and suffix ization. Among them, the stem central means "center", the suffix - ization means "... Hua", and the prefix de - has the meanings of leaving, removing, canceling and opposite. Therefore, it is very accurate to translate it into decentralization

what is the meaning of decentralization

vitalik buterin, founder of Ethereum, published the article "the meaning of decentralization" in February 2017, elaborating the meaning of decentralization. He thinks that we should distinguish the centralization and decentralization of computer software from three perspectives: architecture, governance and logic

Architecture centralization refers to the number of nodes that the system can tolerate and continue to run; Governance centralization refers to how many indivials and organizations are needed to control the system; Logic centralization refers to whether the interface and data presented by the system are like a single whole

blockchain is a unified account book of the whole network, so it is logically centralized, which is beyond doubt. From the perspective of architecture, blockchain is based on peer-to-peer network, so it is decentralized. From the perspective of governance, blockchain makes it difficult for a few people to control the whole system through consensus algorithm, so it is decentralized. The decentralization of architecture and governance brings three benefits to blockchain: fault tolerance, anti attack and anti collusion

five differences between blockchain and traditional distributed system

as a new kind of distributed system, blockchain is often mistakenly regarded as a distributed database or log system. In fact, there is a fundamental difference between blockchain and traditional distributed system, namely decentralization. Now let's look at the main differences between blockchain and traditional distributed systems:

(1) consistency algorithm: what blockchain needs to solve is the Byzantine general problem, that is, there are one or more fraulent nodes in the network, which may deliberately violate the protocol or transmit wrong data, Therefore, Byzantine fault-tolerant consensus algorithms, such as BFT, pow, POS, are often used in blockchain; The traditional distributed system only needs to consider the node failure and communication errors, and often uses consistency algorithms such as Paxos and raft, which can not resist the fraulent nodes

(2) central controller: there is no central controller in the blockchain network, and no node can control or coordinate the generation of ledger data. All nodes coordinate through consensus algorithm to generate consistent ledger. However, the traditional publishing system is often controlled by one organization, which uniformly dispatches all nodes to participate in the calculation

(3) rule making: the rule of blockchain is consensus protocol, also known as consensus mechanism, and consensus algorithm is a part of it. Consensus mechanism is generally designed and developed by a person or a team, and the corresponding proceres are developed for the community to use. This seems to be the same as the traditional distributed system, but the change and upgrading of the consensus mechanism of the blockchain requires the community to have a consensus on it. If no consensus can be reached, anyone can implement hard bifurcation and build another community and chain. This is the decentralization process of consensus mechanism.

2.

The decentralization of blockchain refers to the form of social relations and content generation formed in the process of blockchain development. It is a new network content proction process relative to "centralization"

blockchain is an important concept of bitcoin, which is essentially a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains the information of a batch of bitcoin network transactions, which is used to verify the effectiveness of its information (anti-counterfeiting) and generate the next block

blockchain is unified in the whole network, so it is logically centralized. From the perspective of architecture, blockchain is based on peer-to-peer network, so it is decentralized. From the perspective of governance, blockchain makes it difficult for a few people to control the whole system through consensus algorithm, so it is decentralized

extended data:

characteristics of blockchain Decentralization:

decentralization, not without the center, but by the node to freely choose the center, freely determine the center. In short, centralization means that the center determines the node. The node must depend on the center, and the node cannot survive without the center

in a decentralized system, anyone is a node, and anyone can be a center. Any center is not permanent, but phased, and no center is mandatory for nodes

with the diversification of network service forms, the decentralized network model becomes more and more clear and possible. After the rise of Web2.0, the services provided by Wikipedia, Flickr, blogger and other network service providers are decentralized. Any participant can submit content, and Internet users can create or contribute content together

reference source: network blockchain

reference source: Network decentralization

3. Jinwowo analyzes the decentralized peer-to-peer network of blockchain. Blockchain system is a point-to-point network. All nodes in the network jointly own and maintain all data in the system, and the damage or offline of any node will not affect the operation of the whole system. Decentralization brings greater security and stability advantages to the whole network.

4. The Internet is to eliminate the (information) supply chain with low value and high cost - it is open, interconnected, peer-to-peer, global and decentralized. "
we know that the essence of the market is also decentralized. It automatically implements the decentralized agreement of "exchange of equal value." market economy is based on two deep cognitive foundations: admitting ignorance and embracing uncertainty“ Invisible hand! Therefore, the market must need the low-cost flow of information decentralization, and the Internet has just adapted to the climate of the formation of a global unified market.

5. The decentralization of blockchain refers to the form of social relations and content generation formed in the process of blockchain development. It is a new network content proction process relative to "centralization"
blockchain is an important concept of bitcoin. It is essentially a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, which is used to verify the effectiveness of its information (anti-counterfeiting) and generate the next block
blockchain is unified in the whole network, so it is logically centralized. From the perspective of architecture, blockchain is based on peer-to-peer network, so it is decentralized. From the perspective of governance, blockchain makes it difficult for a few people to control the whole system through consensus algorithm, so it is decentralized.

6. The concept of P2P

P2P is the abbreviation of peer-to-peer. In English, peer has the meanings of "peer", "colleague" and "partner". In this way, P2P can be understood as "partner to partner", or peer-to-peer networking. At present, people think that it has a bright future in enhancing people's communication, file exchange, distributed computing and so on

in short, P2P directly connects people and enables people to interact directly through the Internet. P2P makes communication on the network easier, more direct sharing and interaction, and truly eliminates middlemen. P2P means that people can directly connect to other users' computers and exchange files, instead of connecting to the server to browse and download as in the past. Another important feature of P2P is to change the Internet's current big website centered state, return to "decentralization", and return power to users. P2P seems to be very new, but just as B2C and B2B transplant common things in the real world to the Internet, P2P is not new. In real life, we communicate face to face or by telephone according to P2P mode every day

even from the perspective of network, P2P is not a new concept. P2P is the foundation of the overall Internet architecture. TCP / IP, the most basic protocol of Internet, has no concept of client and server. All devices are the equal end of communication. Ten years ago, all systems on the Internet had both server and client functions. Of course, the later developed software based on TCP / IP does adopt the client / Server Structure: browser and web server, mail client and mail server. However, for servers, they are still peer-to-peer networking. Take e-mail as an example, there is not a huge and unique e-mail server on the Internet to handle all e-mails, but peer-to-peer e-mail servers cooperate with each other to send e-mails to the corresponding servers. In addition, email between users is always a peer-to-peer communication channel. Of course, but in the past five years, the development of the Internet has at least distanced itself from P2P on the surface, and most of the nodes on the Internet can not communicate directly with other nodes. Napster awakens the peer-to-peer networking that is deeply behind the Internet. Napster's file sharing function is a common thing to share directory in LAN. But Napster's success has made people realize the possibility of extending this "peer-to-peer networking" to the whole Internet. Of course, in the eyes of many people, Napster is not pure P2P, it still needs a central coordination mechanism

in fact, many existing services on the network can be classified as P2P. Instant messaging systems such as ICQ, AOL Instant Messenger, Yahoo pager, MSN Messenger from Microsoft and OICQ in China are the most popular P2P applications. They allow users to communicate and exchange information and files with each other. The information exchange between users is not direct, it needs a server in the center to coordinate. However, these systems do not have such functions as search, which are very important for a large number of information sharing. The lack of this feature may be one of the reasons why instant messaging has appeared for a long time, but it has not been able to proce such an impact as Napster

another thing that can be classified as P2P is auction websites, such as eBay. When people summarize the mode of eBay, they use C2C. Is it a bit similar to P2P? EBay is a community that connects people and trades goods. Users can easily search for goods that other users sell. EBay offers some services to make the transaction go smoothly, but the transaction is directly between users. If the concept of "transaction" is extended, C2C is a special case of P2P, where people exchange goods with each other

but if we look into it carefully, Napster and instant messaging give users the ability to communicate directly and eBay allows users to trade directly. At the same time, they destroy the server-side idea of peer-to-peer networking, which has existed since the advent of the Internet, because they need a central server to coordinate, rather than distributed in different parts of the world Many servers in peer-to-peer networking. This is exactly what Gnutella and Freenet constantly claim that they have created "pure" P2P, without P2P service of central server at all.