Securing files/folders?

I've seen a few apps, but didn't like them. I would like one that I can use to secure a folder of an app, but that lets me password protect the folder and any files.
I've seen some that will let you do the same, but you have to decrypt and re-encrypt them every time you want to use them, and then have them secure again. There anything like I'm looking for? Most preferably a portable app, but if there isn't, anything would work for now.