【摘要】Nowadays, “cards” are becoming part of our lives. The cards enable us to obtain different kinds of services conveniently, but may also bring us economic loss if they are used illegally by some malicious third party. A common practice to solve the problem is to ask the user to provide some personal information possessed by the true card holder only. However, the personal information can be leaked if it is not managed properly. To protect the card users more effectively, this study proposes a generalized image morphing technique and a new method for card user authentication. The fundamental idea is to hide the face image of the card holder into some cover data through morphing, distribute the key information for restoring the face image into several different places, and restore the face image through de-morphing when the card is used. Brief analysis show that the proposed method is simple but secure, and can be very useful in different card-based services.