I slapped together a possibly useful php wrapper for highly useful open source tools.  Now you can strip the passwords from your pdfs with only a web browser.  Don’t thank me, thank the guys over at mupdf for pdfclean or maybe my sister for needing my help with pdfs.  check it out: https://be3n.com/toybox/breakpdf/

FYI, it only helps with DRM, not encryption.  enjoy.