need to symmetric encryption in qt app

[FS Lover]

I use Qt with mingw on Windows XP.
I tried QCA but it doesn't work with Qt (app compiles but gives fatal error when trying to execute it).
I tried a compiled version of crypto++ too but it has compiling problems (many undefined reference errors).
I don't know how to get these libs to work.
please tell me a quick and easy way. I need only a symmetric encryption to encrypt and decrypt a file.