Help with type of encryption

[eycaramba]

Hey,

yet again, an encryption-related question. Any ideas which encryption these files could be using?
The *.dec files obviously are the decrypted equivalent to the others. Only thing I noticed is that the first four bytes are the same for both.
Maybe that's a hint?

http://www4.zippyshare.com/v/25456953/file.html

Thank you very much!