There are three main categories of blockchain: public chain, permissioned blockchain and the consortium-led Blockchain. Other categories of blockchain may emerge in the future with the rapid development of technology.
Public Chains are open and transparent. Any individual or institution can initiate a transaction through a Public Chain from anywhere in the world, which is then verified and processed by nodes in the Blockchain. Any miner can compete for the bookkeeping right. The Bitcoin Blockchain is an example of a Public Chain.
The consortium-led Blockchain is semi-public and is usually used within an organization or between members of a consortium. Several nodes are pre-assigned as bookkeepers. The generation of each block is jointly decided by all pre-selected bookkeepers. While other nodes trade and participate in the blockchain, these nodes do not possess bookkeeping right.
Permissioned Blockchains are completed closed off from the public. Bookkeeping rights are centralized with Blockchain technology used mainly for accounting and the recording of internal transactions. Permissioned Blockchains are used exclusively by a predefined group of institutions or individuals.