A payment card comprises an internal virtual account number generator and a user display for online transactions. Offline transactions with merchant card readers are enabled by a magnetic array positioned behind the card's magnetic stripe on the back. The internal virtual account number generator is able to program the magnetic bits encoded in the magnetic stripe to reflect the latest virtual account number. The internal virtual account number generator produces a sequence of virtual numbers that can be predicted and approved by the issuing bank. Once a number is used, it is discarded and put on an exclusion list.