Axantum's AxCrypt is a free, open-source file encryption utility that offers strong symmetric encryption combined with compression, Windows shell integration, and other features. AxCrypt2Go is a portable version of AxCrypt. Since it's a portable tool, it doesn't offer all of the full version's integrated features. Axantum recommends using the fully installed version of AxCrypt as your daily driver and running AxCrypt2Go from your USB flash drive when you need to encrypt or decrypt files when you're away from your main system.
Once you've extracted and saved the program, you can drag it anywhere and run it simply by clicking the executable file. AxCrypt2Go's interface is pure Explorer, with a tree view in the left-side panel and a main window displaying a list view of selected files. The menu bar offers basic File and View options, and the Help menu is really just an About pop-up with a link to the developer's Web site. But the site offers plenty of information about the full version and how to use it. Still, AxCrypt2Go is totally easy to use: simply select the files, folders, or directories you want to encrypt, right-click, and select either Encrypt or Decrypt from the context menu.
We started simply, with an image file. Selecting Encrypt produced a passphrase dialog with a key-file passphrase option. We entered and verified a password and clicked OK. AxCrypt2Go adds an .axx extension to encrypted files; our encrypted, compressed file appeared in the same directory as the unencrypted source, which we'd ordinarily delete if we were planning to protect the data. Decryption is simply the same process in reverse, though the program saved the decrypted file to our Documents folder.
AxCrypt2Go doesn't generate key files, but we could browse to key files we'd created and saved, and select check boxes to retain key files for decryption during session and make it the session default for encryption. While we agree that the full version of AxCrypt is the better solution, AxCrypt2Go is a great companion that makes a good basic encryption tool on its own.