What are permissioned DApps?

Until now, we have been learning about DApps, which are completely open and permissionless; that is, anyone can participate without establishing an identity.

On the other hand, permissioned DApps are not open for everyone to participate. Permissioned DApps inherit all properties of permissionless DApps, except that you need permission to participate in the network. Permission systems vary between permissioned DApps.

To join a permissioned DApp, you need permission, so consensus protocols of permissionless DApps may not work very well in permissioned DApps; therefore, they have different consensus protocols than permissionless DApps. Permissioned DApps don't have internal currency.