Using the PIC micro-controller as a Cryptographic Coprocessor for Digital Watermarking Applications

This paper presents a novel design of a special "addon " hardware module that works as a cryptographic co-processor. It employs a PIC micro-controller to insert a selected digital watermark in a bit-mapped image file. The image file to be watermarked is passed from the PC through the serial port to the cryptographic co-processor. The co-processor inserts the watermark and sends the file back to the PC over the serial port. Serial communication with the PC serial port is performed using the PIC\´s built-in USART. The system can be used for watermarking image files of any size; however, the size of the watermark will depend on the size of the image file. The firmware for the hardware module has been thoroughly tested and simulated using the latest version of microchip\´s development tools. Benefits of this approach include the high level of security associated with this add-on hardware module, because it can be kept under lock and key at a separate place. Different bit patterns can be used as watermarks by simply changing the firmware code or by reading new information from the controller \´s input port