(We recommend reading our article “What Is Blockchain?” by clicking here before reading the article below.) Blockchain networks could be examined as Public Blockchain networks and Private Blockchain networks in terms of accessing data on the system, and Permissioned Blockchain networks and Permissionless Blockchain networks in terms of processing data.
A. Public and Private Blockchains
Blockchain networks are, basically, a series of encrypted data streams. Blockchains that allow anyone to see the contents of these data streams can be described as Public Blockchains. For example, anyone can see all transactions on the Bitcoin network on a block explorer website or by connecting to the Bitcoin network.
On the other hand, Private Blockchains are networks that only allow permitted persons to see the transactions made on the network. Areas where we can see this kind of networks are internal networks of companies, networks created by central banks and networks created by parties for privacy.
**B. Permissioned and Permissionless Blockchains **
Viewing and writing data on blockchain are two separate issues. We covered the viewing data part in the section “Public and Private Blockchains” above. Now we are going to examine the data writing in the “Permissioned and Permissionless Blockchains”.
As an example, on the Bitcoin blockchain, it is stated in the article “Bitcoin: A Peer-to-Peer Electronic Cash System” written by Satoshi Nakamoto that anyone who wishes can become a participant in the blockchain network and take part in the processing of the transfers to the blocks. By this example, it can be said that networks that do not require permission to process data are defined as “Permissionless Blockchains”.
However, let’s suppose that there is a blockchain network that plans and processes a city’s public transportation hours. People should be able to access this blockchain data, but the plans of the public transportation hours must be added by a civil servant. In this case, the network to be used can be described as a “Public but Permissioned” network.
