I'm familiar with J3M, but unfortunately none of the current
   J3M/informacam techniques actually work, as they have no _external_
   verifiability. There isn't actually any information which ties the
   media to a place or a time, it's just information encoded into data
   which could be applied to any document at any time. By factoring the
   network, a geotemporal pkey system would address this problem. J3M is
   good for tying information to a specific device (sort of) - but not to
   a place or a time.
   R

   On Mon, Aug 26, 2013 at 4:58 PM, Lee Azzarello
   <[1]lee@guardianproject.info> wrote:

     Informacam
     "InformaCam is a mobile application for Android that enables users
     to
     inflate image and video with extra points of data, or metadata. The
     metadata includes information like the users current GPS
     coordinates,
     altitude, compass bearing, light meter readings, the signatures of
     neighboring devices, cell towers, and wifi networks; and serves to
     shed light on the exact circumstances and contexts under which the
     digital image was taken. With InformaCam the app starts to behave
     almost like Adobe Photoshop or GIMP, supporting non-destructive,
     layer-based edits to media built on top of Obscuracam."
     [2]https://guardianproject.info/apps/informacam/
     There is a sub-project to standardize metadata called j3m.
     [3]http://j3m.info/
     -lee

   On Mon, Aug 26, 2013 at 7:08 PM, Rich Jones <[4]rich@openwatch.net>
   wrote:
   > This is a small, unfinished idea I had, but I'd be interested in
   hearing any
   > feedback anybody here might have to offer. Normally we talk about
   > cryptography to secure communications, but this is an idea rather
   about
   > verifying the authenticity of media.
   >
   > [Quick backround: OpenWatch is a global citizen media network using
   mobile
   > phones as the basis for a free worldwide press. We care very much
   about the
   > authenticity of citizen media, and have designed some systems which
   attempt
   > to improve the verifiability of citizen media.]
   >
   > The problem is that sometimes media artifacts are presented as a
   record of a
   > current event, when in fact they from different events. An example of
   this
   > was when images of a marathon race in Istanbul were presented as
   images of
   > the recent Occupy Gezi protests.
   >
   > Now, imagine the globe divided into a grid coordinate system, say
   100,000
   > units (or perhaps 232, if IP rather than physical address is to be
   used).
   > Based on their physical location, reporters can contact a server and
   are
   > assigned a key with which to sign or encrypt their media to. This
   then ties
   > a media object to a physical space. This can be further improved to
   include
   > both time and space by dividing a space-day into a number of units,
   suppose
   > 1440, such that different keys would be handed out at different times
   of the
   > day, thus further tying a document to a moment in time as well.
   >
   > Does anybody know if any systems like this have ever been discussed
   or
   > designed in the past? I suppose this is somewhat similar to the
   RSA-keyfob
   > system, although this allows for anonymous access without
   pre-arrangement as
   > well.
   >
   > R

   --
   Rich Jones
   OpenWatch is a global investigative network using mobile technology to
   build a more transparent world. Download OpenWatch [5]for iOS and
   [6]for Android!

References

   1. mailto:lee@guardianproject.info
   2. https://guardianproject.info/apps/informacam/
   3. http://j3m.info/
   4. mailto:rich@openwatch.net
   5. https://itunes.apple.com/us/app/openwatch-social-muckraking/id642680756?ls=1&mt=8
   6. https://play.google.com/store/apps/details?id=org.ale.openwatch&hl=en