[Potential Spoilers] Official SKYFALL Photo Thread (Part I)

Here's my theory of what the black box is:

An "insurance policy".

The clapperboard for the scenes on the rooftop show it is scene 172, which will come late in the film. I think this could actually be the final scene before Bond goes after the villain.

During the course of the film, Javier Bardem's villain will wreak havoc on MI6. He does this through an ally that for some reason - political, perhaps - Bond cannot touch directly. That ally, however, can hurt Bond. So before he goes after Bardem, Bond puts together his "insurance policy": some kind of evidence against that particular person, evidence which could destroy their reputation if it ever came to light.

I think Eve will play a prominent role early in the film, before stepping out of it when she feels that she is in too deep. Up until this point, she has endeared herself to Bond - perhaps she has proven to be very creative in her work (for example, she does something like Bond tricking the Quantum members into identifying themselves at the opera). Knowing full well that he cannot account for everyone under Bardem's influence, Bond passes the box and its insurance on to Eve, because he knows that she will make sure it is handled properly. If Bond does not get in contact with Eve by a certain time and date, she will make sure its contents are released. This will effectively buy Bond safe passage to the final confrontation with Bardem. Once the trade takes place on the rooftop and Eve leaves (possibly with Bond standing and watching her go), we cut to Scotland for the finale.