Method and apparatus for preventing unauthorized access of memory devices

The invention pertains to the protection of data stored in digital memory from unauthorized access. The invention is particularly adapted for use in connection with removable non-volatile memory devices such as flash memories and digital film cards. A method and apparatus for preventing unauthorized access to data stored in memory utilizing two programmable logic devices as front end interfaces for the memory device and the data processing device which is to utilize the memory device, respectively. The two programmable logic devices are complementary programmed such that the signal lines between the data processing device and the memory core and/or their timing are scrambled at the interface between the two programmable logic devices, but are properly ordered with the proper timing at the interface between the memory core and the first programmable logic device and the interface between the data processing device and the second programmable logic device.