What is the difference between decentralized and permissioned blockchain?
Although a common misconception, the question itself is wrong as every blockchain is essentially decentralized. Decentralization and the permission-based nature of blockchain are different-level concepts, so they can’t be compared. In other words, a blockchain can be both decentralized (architecturally speaking) and permissioned (politically speaking).
The better question would be what is the difference between a permissioned blockchain and a public blockchain.
Public blockchains are often described as community owned. Users of these blockchains can make transactions and use the blockchain’s functionality without anyone’s permission.
For an example, you don’t need to look any further than Bitcoin and Ethereum. The former is the most basic, first-generation blockchain that enables the eponymous cryptocurrency. Ethereum is more advanced, as it has enabled smart contracts and decentralized apps (DApps).
Permissioned blockchains, by contrast, operate on a system of permissions. This means that they can’t be used by someone who isn’t registered or permissioned. Using this permissioned blockchain technology is a sound decision for major businesses and organizations as it does not allow for any unauthorized use.
The most prominent examples of permissioned blockchains are L3COS, Hyperledger, Quorum and R3.