we have to protect pdfs with password (reading and printing allowed only) using Adobe Acrobat Pro. The pdfs are offered for download on an official homepage and there are strict rules concerning the documents. When we open the protected pdf with Acrobat Reader or similar software in our local working area, everything works fine. Now we found out, that the pdf was protected using the Internet Explorer, but was NOT protected using Firefox! Maybe the effect happens also with other browsers. How can we manage that problem? Thank you very much for your help.
There's not much you can do about it. The PDF plugin in Firefox (and yes, other browsers as well, like Chrome and Safari) is sub-par.
You should complain to the developers of these browsers about it.
You should have received a warning, when setting security, that some third party tools may not respect the security. It means this.