What is a Permissioned Ledger?
As a matter of fact, the Permissioned Ledger is the blockchain itself. Anyone can read the blockchain and anyone can make legitimate changes. Any miner can also add a new block to the blockchain with respective computer power, provided that participants follow consensus rules.
Cryptocurrencies are completely decentralized. They are also called “censor resistant” blockchains. Therefore, these blockchains are mostly public. However, this is not the only way to create a blockchain.
Blockchains can also be created in such a way that they require permission to read information in the blockchain. This limits the parties that can perform transactions in the chain. It also determines who can operate the network by writing new blocks in the chain.
For example, Ripple performs a permission blockchain (also known as a ledger). The startup determines who can act as a transaction validator in the network. Ripple determines its own transaction validators while maintaining its own nodes worldwide.
Variations of the Permissioned Ledger
A blockchain developer may decide to make the system readable for everyone with records. It may also choose to allow only certain individuals to run a node and keep the network secure. Other tasks involve transaction verification or mining. It’s a mixed bag that is reflected in different options developers choose to test their technology.
Permissioned Ledgers (blockchains) may or may not contain a “work proof” requirement or similar for the system of nodes. There are private blockchains that do not use these proofs. These don’t actually constitute blockchains at all but are simply distributed ledgers.