Checksum JPEG data (not the whole file)

Question

Are there end-of-exif / end-of-xmp / end-of-iptc / start-of-data markers that I could use to get a checksum of just the data part of a jpg / jpeg (and other image formats)?

Answer 1

I think this question is related to this one Compute hash of only the core image data (excluding metadata) for an image, https://stackoverflow.com/a/10075170/890106 gives an element of answer if you're looking for code.

It might not works with all JPG variants though : some of them can embed multiple images (MPF / CIPA Multi-Picture Format, more informations at http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/MPF.html) and you might still have some metadata. Also, some software put an UID in the form of --[0-9A-F]+-- at the end of the file and it shouldn't be read. Safest solution if probably to checksum pixels (though you can still have influence of orientation, color profile, ..).