A method and system of performing secure credit card purchases in the context of a remote commercial transaction, such as over the telephone, wherein only the customer, once generally deciding upon a product or service to be purchased, communicates with a custodial authorizing entity, such as a credit card company or issuing bank wherein such entity has previous knowledge of the credit card number as well as custodial control of other account parameters such as interest rate, payment history, available credit limit etc. The customer supplies the custodial authorizing entity with the account identification data such as the credit card number and a requested one of a possible plurality of predetermined payment categories which define the dollar amount for the purchase and specific, predetermined time parameters within which authorization by the custodial authorizing entity will remain in effect. The custodial authorizing entity then generates a transaction code which is communicated exclusively to the customer wherein the customer in turn communicates only the transaction code to the merchant instead of a credit card number. The transaction code is indicative of merchant identification, credit card account identification and a designated one of the plurality of predetermined payment categories.