I've protected one of my pdf document with adobe acrobat and it works just fine. But when I post it in my web site it isn't protected anymore. The link to my pdf goes directly to it without asking the password. How can I get it protected online?

The file is protected on my computer and in my drive. But it seems like when I added it to my server to be able to add it on my web site the protection did not follow. I wonder how I can have my pdf protected when it's a link on my site.