MIFARE applications (MIA) are organized in at least one sector comprising sector data being arranged in data blocks and a sector trailer. A compressing method for MIFARE application comprises: searching for consecutive occurrences of same data values in the sector data and replacing the detected consecutive data having the same data value by a sequence comprising said data value and a number indicating the number of consecutive sector data having that data value; and/or searching for all different sector trailer values and replacing all sector trailers by references to respective ones of the different sector trailer values.