Secure data transfer between a chip card and a chip card reader whereby frequency monitoring is used to ensure that secure data is not fraudulently obtained by varying the data transfer frequency

摘要

Chip card reader (11) has an interface (5) for exchange of information with a chip card (6). The chip card reader contains a first clock (1) with a first operating frequency (f1) for control of the time flow of data transfer. The card reader has a second clock (2) that operates with a second frequency (f2). The reader also contains an element that uses the second frequency to check if the first frequency used in data transfer lies within acceptable limits. The invention also relates to a corresponding method for secure data transfer between a chip card and a chip card reader.