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.