Elsevier embeds a unique code in every academic journal article users download
Big brother likes that
Academic Journal Claims it Fingerprints PDFs for ‘Ransomware,’ Not Surveillance[…]
But what can be done about this kind of sh*t f*ckery?
exiftool -all:all= <path.pdf> -o <output1.pdf>
qpdf --linearize <output1.pdf> <output2.pdf>
To remove all metadata, you can use dangerzone or mat2
here's a shell script that recursively removes metadata from pdfs in a provided (or current) directory as described above. For mac/*nix-like computers, and you need to have qpdf and exiftool installed | by jonny_saunders, Source:
https://nitter.42l.fr/json_dirs/status/1486120144141123584
Alt. link.:
https://twitter.com/json_dirs/status/1486120144141123584
https://gist.github.com/sneakers-the-rat/172e8679b824a3871decd262ed3f59c6
You could also use metadata cleaner
https://gitlab.com/rmnvgr/metadata-cleaner/
Further reading to the motherboard i.e., vice article