Permissioned blockchain (private blockchain)

In a permissioned or private blockchain an operator or governing body decides who may run nodes, produce blocks and see data. Participants are identified, so the network can use fast voting-style consensus instead of energy-hungry mining or open staking. Frameworks such as Hyperledger Fabric and Corda were built for this model.

Companies and banks use private chains when they want a shared, tamper-evident record but cannot expose client data or let unknown parties validate. Typical pilots cover trade finance, interbank settlement, supply-chain tracking and tokenised securities, where regulation requires knowing exactly who operates the infrastructure.

Because the validators are a small known group, a permissioned chain inherits the trust assumptions of a traditional consortium: members can agree to rewrite history or exclude a participant. Critics argue many such projects add complexity without real benefit over a replicated database, and networks built on different private platforms often struggle to interoperate.