Help!

[morcroft]

As far as I know, Microsoft tightened up their encryption from 2007 onwards and are now finally doing it properly - the Office Open XML format uses 128-bit AES encryption which means that with a decent password it's pretty much beyond economic recovery, at least with your own equipment.

I can't see any free tools for docx files.

I've just looked at http://lastbit.com/office2007password.asp - they are a data recovery service and will run a full attack on the document at their datacentre and say they will be able to determine whether or not they can decrypt in a week and will refund the 79 euro fee if they cannot (standard service: there's a more expensive express version). I'd honestly say that's not a bad deal considering the kind of hardware they have to throw at the problem. Chances are that your password isn't complex enough to defeat that kind of attack.

So it really depends on the strength of password you're likely to have used. If you think you'd have used a real word then a dictionary based attack is possible, but offhand I can't see anything that will do it for free on docx format files. Earlier Word files are trivial to crack and there are multiple tools - see http://pcsupport.about.com/od/toolsofthe...covery.htm for three.

If you were my client I'd say spend the money and learn the lesson - but I suspect you can't afford to spend 79 euros on recovering the document.

Sitting there and trying to work through all the passwords you commonly use and your own thinking style is the most likely to be successful without spending money, though. Make a list of all passwords you've tried as you go.

Sorry not to have a better answer for you.

-- disclaimer: I am not a data security professional but have looked into this stuff a little for work. I have no connection with any companies mentioned in this post.