So, when we talk about Blockchain, we think of it as a network where there is a single ledger, the copies of which are maintained by all the nodes of the network. The transactions are broadcasted to the network after it is confirmed and the consensus makes sure that all nodes in the network are in sync. This was true for the inceptive period of the blockchain, when it all started with Bitcoin blockchain somewhere in 2009.However with the evolution of this technology, and the need of inculcating flavours of privacy and permissioning, Blockchain was categorised into —Public, Private and Permissioned Blockchain.
Going back to the time of the Great Recession when Satoshi Nakamoto came up with a revolutionary invention of Bitcoin blockchain, the idea was to build a system of money transfer between two individuals without intervention of a third party or Banks. The intend was to provide one utter liberty on one’s own finances. As years were passing by, the tech world started exploring it all the more and experimenting with the astounding tool in such a way that its potential could be realised to the maximum. And we all know what followed was the birth of different major blockchains like Ethereum blockchain, Hyperledger Project and many more. The horizons were now widened for this technology. It could now be used for building software applications which we commonly know as D-apps today. Dapps or Decentralised applications are nothing but applications built on Blockchain Technology.
The initial blockchain was modified to include features which make it feasible for use in different industries and help solving various problems in todays world.
Blockchains are categorised into :
Public Blockchain
A network of nodes which is absolutely open for all. You , me or anyone in the world can become a part of the network freely, can read , write or even exit the network whenever we wish . Nobody owns this network or is a master of the network here. Also there is a factor of anonymity maintained here. Nobody’s identity in the network is revealed which indeed has its pros and cons. An example of this is Bitcoin blockchain. If you wanna join the Bitcoin network, you can simply do that by becoming a node of the network. When I say becoming node of the network, it means copying entire bitcoin ledger or data on to your machine and making your machine in sync with the ledger . Now there is a process for hosting a node in network obviously and in fact you can decide what sort of node do you want to run/host, so nodes are also of different types but that’s a separate topic, for now you need to get into that. Now if the original ledger is updated i.e. any other transaction is added in the block, your machine will also record and save that copy to be in sync with the network or to be up to date with the network. Joining the public networks usually includes rewards and incentives which keep up the network. This was pretty much about public blockchains. Ethereum is also a very popular public blockchain.
Private Blockchain
As the name suggests, private means it is private to some body. In this type of Blockchain network, there is a regulation to the entry of members into the network. Hence this type of blockchains looses the flavour of decentralisation though but is a good fit for use cases which are enterprise or business specific. A network operator or a specific node invites the parties/members to join the network and only those which receive the invitation are allowed to join the network. In simple terms, it is a network that somebody owns but in that network everyone shares the same copy of data. For a simple example: lets say you want to have a private blockchain, now this blockchain should have properties of ethereum blockchain, so you can build your own private ethereum blockchain which will be a copy of public ethereum network(the one developed by Vitalik Buterin) but this blockchain of your will be in your control. It will have all the features of Ethereum blockchain(like concept of mining , pow consensus algo), the only difference will be that unless you share the invite to other members to join your blockchain , they wont be able to join it. Hope you are bit clear about private blockchains.
Permissioned Blockchain
A permissioned blockchain network is a network where entry to the network is regulated i.e no node can join the network without verification of its identity. This verification is done by special types of node operators. Hyperledger fabric is one such example of permissioned blockchain. Unlike public blockchains , the identities of nodes in the network are not kept anonymous, hence maintaining an element of security and trust among network participants. The list of all the participants involved in the network is maintained in the network , not accessible by members of the network though generally. Like private blockchains it also has the element of centralisations , though it still has a distributed ledger, that is all nodes in a network maintain same copy of ledger. Now there are different permissioned blockchains with their own customised properties which is intended to make certain problems easy. Every permissioned blockchain is developed such a way that it revolves around some specific problems or industries, though not restricted to a specific industry. As you keep on digging more about blockchains, you will get a fairer idea of this.
Permissioned blockchains were developed for real life enterprise use cases where sensitive information has to be shared on a need to know basis. For example: banks now a days are adopting blockchain and they make use of permissioned blockchain in their use cases and it makes sense in this case as data from banks can’t be revealed just to anybody, it should be restricted to some specific members only that bank allows.
That was all regarding the types of Blockchain !
Happy Blockchaining !
