Digital Introduction (was: bar code scanners on the XO)

[Morgan Collett]

Ivan Krstić wrote:
> We have code in git that encodes arbitrary (but size-constrained) data
> as a redundant datamatrix barcode and shows it on the screen, and code
> that performs image analysis from a camera capture when one XO is
> pointed at another with such a barcode on the screen to decode the
> original data:
>
>      <http://dev.laptop.org/git?p=projects/barcode;a=tree>
>
> The original purpose was to facilitate a physical public key exchange
> ("digital introduction") by holding two laptops up to one another.

Interesting. I wondered about this as a friending* mechanism to seed
Presence when we start filtering server presence** to mainly your
friends and a few other random people. While we are planning to add
search, this would be a much more fun way to get people near you to show
up on your mesh view. I didn't realise there was already code :)

(The other idea was to do it via audio, inspired by the Distance activity.)

* We still need to get groups adequately defined, AFAIK.
** Daf's working on Gadget for this.

> It wasn't scrapped; it's on the backburner because higher-priority  
> issues needed to be dealt with first, and the subsystems that would  
> most benefit from an out-of-band public key exchange (like Telepathy)  
> can't deal with KCM-style PKI yet.

We did make some assumptions about Key Continuity Management and had it
in mind with certain aspects of Presence Service. We have ideas on how
it could be implemented in Gabble and Salut. When we meet with Jon
Herzog we can make sure we're on the same page and see how to move
forward with this.

Morgan