There are numerous reasons as to why you would want to encrypt and protect your PDF file. It may be the case that you share a computer with others, and you don't want them having access to the file, thus you have a password applied to the file so that only you can read it.
It may also be the case that you're sending a PDF file through an email, and are worried about it being intercepted. Again, having it decrypted is the perfect solution to prevent someone from reading your document.
Imagine another scenario in that you're distributing an ebook, but you don't want people copy and pasting the content, nor do you want them to make any changes to the ebook (such as adding their own watermark to pass it off as their own) or even allow readers to print it off to pass onto others. In all of these cases, they could then pass the ebook off as their own work, stealing your content and making money into the bargain! This really is a risk that many ebook writers take when they publish their works on the internet.
However, the problem with PDF encryption is that it's an extremely expensive process, usually involving expensive software. Whilst you can make a PDF file in Word, you can't protect the file, allowing users to do all the things you don't want them too. Looking around the internet, I've noticed that numerous companies offer their software listing all of the above for $400+. Now, with the current economic climate, no one can afford to pay that amount, even though they want their files protected. The other end of the spectrum is that some websites and freeware software offer to encrypt the file for you for free. However, from my own personal experience of using them, the files usually become corrupted, leaving them unreadable.
I have the ability to successfully put a AES 256-bit (high protection) encryption on the files that you have. The benefit of this is that this encryption method is near enough unbreakable, meaning your content is completely safe. I am able to do all the points discussed above, and return the file to you usually in the same day. The price is dependent on how much you're wanting done. Currently, the price starts at £5, and goes up to £15 per PDF file. I will use the password that you give to me. For more details on this, please feel free to contact me through my profile and hitting on the 'Contact SolveMyMaze' link and I'll get back to you as soon as possible.