A permissioned ledger is a variant on the blockchain used by certain cryptocurrencies. Bitcoin’s public blockchain allows any party to read the chain as well as make changes and write new blocks (as long as the rules of blockchain are followed). By contrast, a permissioned ledger is a type of blockchain that requires permissions to perform some or all of these actions. Ripple is a prominent cryptocurrency that utilizes a permissioned ledger in its blockchain. Ripple decides who can be a transaction validator on their network, and it has partnered with organizations such as MIT and Microsoft to serve as transaction validators.