Bitcoin is designed to be a cash replacement using digital cryptography. As such, one of the design decisions was to make transactions non-reversible (the cond

Bitcoin is designed to be a cash replacement using digital cryptography. As such, one of the design decisions was to make transactions non-reversible (the conditions where this would not be true aren't relevant). Basically once the transactions of originating account, destination account, and amount is entered into the distributed ledger/transaction log, it can't be removed, since the majority of systems believe it. Thus is the original account tries to use those same "coins" (really tokens) the network would reject it, as that account not having access to those coins.