Classification of blockchains
There are various types of blockchain technology. Initially, the blockchain technology presumes complete freedom and independence of the chain, in which there is no single administrator. However, interest of large companies and financial institutions in the new technology led to the emergence of more centralized forms of blockchain, when there is a centralized control system while distributed data are preserved.
Such transformations allow us to talk about different types of blockchains: public blockchain; blockchain, which belongs to the consortium and completely private block (the classification of Vitalik Buterina, the creator of the Ethereum platform). They differ by the level of access to the information of participants in the network, as well as their ability to influence its development.
Types of blockchain
Any person in the world can get an access to public blockchains. In the blockchain topology, this means that he or she can send transactions and wait for their inclusion if they are valid, and also participate in the consensus process, that is, determination which blocks will be added to the chain.
Unlike conventional economic systems that are strictly regulated and centrally managed, public blockchains are protected by the principles of crypto-economics. Crypto economics is based on a combination of economic incentives and cryptographic verification of data. According to these principles, the influence on consensus in making a decision is proportional to the volume of economic resources.
Such systems are generally considered to be "completely decentralized.”
Bitcoin and Ethereum are the most popular examples of public blockchains. The public nature of the blockchain allows these platforms to be used to make direct transactions between users without intermediaries.
Blockchain, belonging to consortium
Another types of blockchain are consortium blockchains. Consortium blockchains are controlled by a pre-selected set of nodes. As an example Vitalik Buterin mentions a system of 15 financial institutions, each of which manages the node, and 10 of which must confirm each block to be recognized as valid and added to the chain.
The right to read the block chain can be open to public, or limited by participants. "Hybrid" systems are possible when the root hashes of blocks are public, but all members of the blockchain can perform only a limited number of requests and transaction confirmations of some parts of the blockchain. Such chains can be called "partially decentralized.”
R3 (full name R3 CEV LLC) — financial and technological research company. It works with a consortium of 70 large financial companies (including Bank of America, Goldman Sachs, Citigroup, National Australia Bank, Royal Bank of Canada, Sumitomo Mitsui Banking Corporation and others) in the development of the use of blockchain technology in the financial system.
Hyperledger — is an umbrella project that deals with blockchain with an open source code and related tools. The Linux Foundation was launched to support the joint development of distributed registers on the basis of the blockchain. Cisco, Hitachi, IBM, Intel, NEC, J.P. Morgan, SAP and others are among the participants.
Digital Trade Chain Consortium — a financial blockbchain platform that IBM is developing for a consortium of seven large European banks, including Deutsche Bank, HSBC, KBC, Natixis, Rabobank, Societe Generale and Unicredit. The platform will be oriented towards small and medium business.
The platform startup is planned by the end of 2018.
Last but not least type of blockchain technology is private blockchain.
Fully private blockchains is a chain of blocks in which the recording of new blocks is assigned only to one organization. The permission to read can be public or limited to some extent.
There are additional options, such as database management, audit, and so on, within one company, when in many cases public access will not be necessary. Although it is impossible to go without it, when a public activity report is required.
https://chain.com/ — is a technology company that cooperates with organizations for the creation, installation and use of private blockchains in the field of financial products and services.
https://www.multichain.com — is an open platform for the establishment of private blockchains.