I am a fan of TrueCrypt and I guess it's the best encryption tool available. As far as I understand, TrueCrypt created encrypted containers which acts a place to store files.
I would like to encrypt a single file. Preferably with a password and a special key file (like in TrueCrypt).
It would be great (but not mandatory) if the file doesn't require any third party software to encrypt and decrypt, in the sense that I provide the password and key to the file directly.