Challenger Encryption software

I was browsing for some software for encrypting just folders (windows7).
Something like cloudfogger, when I found this:

http://www.encryption-software.de/challenger/en/index.html

Does anybody know it?
Lot of info are still in German, but I could not find an evidence of the encryption algorithm or other details.

Actually I am looking for something open source (and that is the reason because I wanted an alternative to cloudfogger) but JUST for folders.

 

http://www.techsupportalert.com/best-free-file-encryption-utility.htm

You can just include the folder in many different encryption programs.