More Design Of Bitcoin Blockchain For a broader coverage related to this topic, see Blockchain. Number of unspent transaction outputs The blockchain is a public ledger that records bitcoin transactions.[50] A novel solution accomplishes this without any trusted central authority: the maintenance of the blockchain is performed by a network of communicating nodes running bitcoin software.[9] Transactions of the form payer X sends Y bitcoins to payee Z are broadcast to this network using readily available software applications.[51] Network nodes can validate transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other nodes. The blockchain is a distributed database – to achieve independent verification of the chain of ownership of any and every bitcoin amount, each network node stores its own copy of the blockchain.[52] Approximately six times per hour, a new group of accepted transactions, a block, is created, added to the blockchain,