A system and method to improve on the security of credit cards when money needs to be charged or transferred by assigning a different charge number to every transaction. A charge number is a combination of the card number and a random number that is generated through a user initiated preauthorization phase. A temporary preauthorization number is issued for a maximum amount to be charged to a specific merchant. Preauthorization output is passed on to the merchant for verification and deposit purposes. A specially designed cellular phone or PDA can be used in lieu of a charge card, in which case the generated preauthorization number can either be stored in a removable memory, or be directly sent to the merchant's charge machine. The card/charge-device does not contain all of the information required for a successful transaction, therefore security is maintained despite its loss or theft of numbers.