The Adobe Air program was basically just a front end to display and decrypt everything. I could never get it to work on Linux so I never actually even looked at it except the screenshots in the help document.

All the files are named well like NGM_1918_04_125.jpg

National Geographic Magazine, year 1918, 4th month (April), page 125

Yeah, it was annoying but I ran a for loop on every file in the 80GB or so to translate it to normal JPEG. It took about 24 hours and that was 10 years ago on a much older computer.