Each Bitcoin is identified, digitally, by a long chain of code called a “hash” (think, serial number). The Bitcoin’s hash remains with it forever. Each user has a “wallet,” where they’ll store their Bitcoins. These wallets have their own serial number-type identifier, called a “private key,” which identifies that specific Bitcoin being owned by that specific owner for that period of time. When a transaction is executed between two parties, the transaction is given its own serial number, called a “nonce,” which is an arbitrary number used only once in any cryptographic communication. 

The private keys for every single transaction will remain on the Bitcoin’s line of code for its entire life, creating a chronological “chain” which will identify it to the exclusion of others. If hundreds of transactions are being conducted every minute, the network will calculate that all the chains add up, so to speak. The architecture relies on mathematical certainty, so duplicating or predicting a chain’s path is nearly impossible. The broad network of mining computers will communicate with one another to confirm that the transactions they’re working on match up and coincide with the other hundreds of transactions being processed at that moment. As more transactions occur, the chains become longer and Bitcoin transactions, in theory, become more secure.  Verification takes about ten minutes.