Ask HN: Tamper resistant geolocated pictures

In this time of easy Photoshop for everybody, I think often about how useful it would be be able to create have digitally signed pictures with time and geolocation, so that it would be very easy to know if the picture (with its location and time) could be trusted or not.

Intuitively, I would think that it would be impossible to give this kind of guarantee with a software-only solution that ran on standard smart phones, as it would be easy enough to run the software on a development virtual machine that could be undetectable by the software, and could feed any picture and GPS data the faker wanted.

On the contrary, with a hardware solution which integrated the camera, GPS, end encryption on the same chip, registering also the focus, exposition and other data, I would expect the system to be much more difficult to tamper with.

So what I'd like to ask anybody expert in the field is:

* is there anything like this already on the market, or being worked on? Any chance to see something like this hit the consumer market anytime soon?

* how easy would it be to trick a dedicated hardware solution using fake GPS signals?

* does any cell phone on the market have any hardware encryption solution that would allow creating a difficult-to-tamper software solution?

Thx!