Password protect file in OSX?

There's still no way to password protect an individual file short of putting it into a disk image.

 

If it's an iWork document you can set one with the Inspector.

 

It's a pleasure. Next time, let us know more details, i.e. what type of file it is (if it is a specific file, if it's just a general question than of course nevermind that).

-BugBytes

 

If its a Word Document you can also password protect it in Word.

 

...Spoken as if that's something bad! Truly, that's a very powerful capability.

You can make a nice encrypted disk image using Disk Utility. It's a great way to keep things private in Dropbox and other cloud-storage services. See http://unvexed.blogspot.com/2011/06/how-to-keep-things-secure-in-your.html for suggestions.