The present invention relates to a credit card comprising a card body, which comprises fingerprint reading means providing fingerprint signals representative of at least one fingerprint from a card user, when at least one finger of said user is pressed against said fingerprint reading means. Said card body further comprises data carrier means holding at least card owner fingerprint data and secured data, and fingerprint authentication means for activating said secured data. The card body further comprises an electrical power supply delivering electrical current to at least said fingerprint reading means. Accordingly, there is no need for an external electrical power supply, and thus the existing standard card reading systems, such as ID-card readers, money transfer machines such as ATM's and the like may be used in conjunction with said credit card. Thus, investments into new standard reader systems are not necessary in order to improve the security of the secured data carried by the credit card. A complete and self-contained automated authentication process is conducted prior to communication concerning said secured data being established between said credit card and any of the existing ATM's on the market today, irrespective of type (automated or manually operated), manufacturer, version, or geographical position of said ATM and of credit card use.