I have a a file with important data that I want to password-protect. I basically want to be prompted for a password every time I try to open the file. I tried TrueCrypt but it doesn't seem to prompt for a password every time you try to open the file (well, unless I missed something).
As a simple workaround, I decided to use WinRAR for this task (by adding a password to the archive). It works great and all but I have a little concern. Everytime I open a file with WinRAR it decompresses the file to a temporary folder. Now I'm worried that the data can be accessed in the temporary folder. I don't know if WinRAR deletes the content of the temporary folder later but even if this is the case the content can still be accessed by some utility (one of those utilities that allow you to view/save deleted files) so it doesn't seem like a secure option to me.
My questions are, is my understanding about how WinRAR works correct? If so, is there another simple (and secure) way to password protect a file?