If you’re 100% organised, there’s a chance you may not need to recover a password from a PDF file.

I’ve got a lot of PDFs scattered over my hard drive and some of those have a password attached to them.

Usually I rename them so that the file name tells me what the password is. But occasionally I don’t do that and then need to hunt through emails or MSN chats to find what the password was.

Other people I know get sent password protected PDFs at work and they either have to add to their collection of Post It notes or find somewhere else to store the password.

Then there are occasions when you or someone else has password protected a PDF with a “memorable” password that then escapes everyone.

So, what can you do to retreive a lost PDF password?

If it’s a file you created yourself, the obvious route is to try all your usual passwords. (Go on, you can admit it, you usually use one of a handful of passwords!)

If it’s a file someone else created, you can try guessing what they may have used.

Sometimes you can get lucky with those techniques.

And sometimes you can’t.

Which is where PDF Password Recovery comes into play.

It’s a program that does the hard work of recovering PDF passwords for you.

The program’s interface is simple, which is good news as it’s not something you’re likely to use often and you wouldn’t want to spend time working out what to do.

You select the PDF file, choose whether you want it to perform a “dictionary” attack using one of the two dictionaries supplied with the program or – if you think the person setting the password has been good at their job – with a “brute force” attack.

If the PDF has been protected with a simple password such as a common word then the dictionary recovery works well.

If it’s been better protected – for instance, if someone has set their password to a good length and has used numbers, letters and other characters – then you’re in for a longer wait…

If you’re not using the computer that’s doing the password recovery for much else, you can set the program to high priority. So if you’ve got a nasty password to crack, you can click this option and leave your computer on overnight.

There’s also a pause option if you find that your computer is slowed down too much. It’s unlikely you’ll need this on a modern machine unless you’ve set the high priority option and you need to do another processor intensive task.

One of the bonuses that comes with the software is a password generator. This works OK and will give you passwords that aren’t easy to crack. Although personally I use this online random password generator. It’s the place I go to when I want to get a reasonably strong password that won’t get cracked easily.

To test the software, I gave it a PDF file with a 7 letter, non-dictionary word.

Although I knew the password’s length and that it was only a mixture of letters, in real life I wouldn’t have that kind of information.

So I ticked all the boxes for possible things the password could contain and asked the program to check all lengths from 2 to 8 characters, using a brute force attack.

As is fairly normal for me, I was also running several other programs on my PC at the time and had about a dozen tabs open in Firefox plus my email program, MSN and Skype. Which meant Windows was reporting 100% CPU usage.

The PDF password recovery software checked about a thousand potential passwords  per second (actual figures were between 789 and 1164 if you really want to know).

It also told me how far through the test it was out of the 33 million possible combinations that it might have to check.

And it found the password, which is obviously the result I wanted.

Verdict

A PDF Password Recovery tool is the kind of program that you won’t need often but when you do, you want something that works quickly and efficiently, with as little interaction from you as possible.

The price is good – if you choose the download option, the $14.95 is very reasonable. The competition I found was between $29.90 and $60.

You can download your copy of this PDF Password Recovery tool here.