[xnull1guest]

We can't really know. There is no way to be perfectly certain.

That said one can apply an Occam's calculus using whatever information and reasoning you do trust. I personally trust that, whomever the #GOP was, they were motivated by SONY's role in developing "the movie of terrorism". This seems to me to be consistent with what the group published and with their 'Christmas surprise' showing collaboration between the State Department and SONY on the development of the movie related to its diplomatic value - something I don't think the NSA or allies would do. So I think the group had NK sympathies in mind. Granted, this doesn't rule out attribution to other states or hacktivists who hold these sympathies.