A database that is consensually shared and synchronised across multiple sites, institutions, or geographies, accessible by multiple people. Unlike with a distributed database, there is no central administrator. It allows transactions to have public witnesses. The participant at each node of the network can access the recordings shared across that network and can own an identical copy of it. Any changes or additions made to the ledger are reflected and copied to all participants in a matter of seconds or minutes. A peer-to-peer network is required as well as consensus algorithms to ensure replication across nodes is undertaken. One form of distributed ledger design is the blockchain system, which can be either public or private.