What is the difference between decentralized and permissioned blockchain?
Although very popular, the question itself is wrong. Every blockchain is more or less 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 and permissioned.
The right question would be what the difference between a permissioned blockchain and a public blockchain is.
Public blockchains are often described as community owned. Users of these blockchains can make transactions and use the blockchain’s functionality without special permission.
For an example, don’t look 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. This technology is a great choice for major businesses and organizations, as it does not allow unauthorized use.
The most prominent examples of permissioned blockchains are L3COS, Hyperledger, Quorum and R3.