Unpermissioned Ledger
An Unpermissioned Ledger is – in contrast to a Permissioned Ledger – a ledger where anyone can download the software, submit messages for processing and/or be involved in the process of authenticating, verifying and reaching consensus. While an unpermissioned ledger will typically use a consensus protocol for determining what the current state of a blockchain should be, it could also use another process to determine that state. One way of using another process could be to use an administrator or sub-group of participants. Such systems are typically controlled by no-one and the participants are usually pseudonymous.