A dynamic credit card is provided in which a secure credit card number (e.g., a secret/hidden credit card number) is encoded based on a timing signal (e.g., an internal counter) to provide a dynamic credit card number. This dynamic number may be displayed to a user via a display (e.g., so that online...http://www.google.com/patents/US20080054081?utm_source=gb-gplus-sharePatent US20080054081 - DYNAMIC CREDIT CARD WITH MAGNETIC STRIPE AND EMBEDDED ENCODER AND METHODS FOR USING THE SAME TO PROVIDE A COPY-PROOF CREDIT CARD
