Writer Job in Austin, Texas

I'm searching for a writer that has experience create code to secure and encypt files to work within Marine GPS / Navigation systems. Possibly even find a way to secure or lock an SD card (most GPS units use SD cards for transferring data from one machine to the other). The file will also have to be secured on the GPS unit while allowing the unit to display the custom data on the screen. Possibility of writing code for up to 10 different Marine GPS brands. Project will start with Lowrance, Garmin, Hummingbird, and probably one other Marine GPS system. Pay is negotiable. Prefer local to Austin, TX.