identifying which builds are signed

[Mikus Grinbergs]

> olpc-update is presently only runnable on machines which have already
> passed the boot-lock; therefore its operation does not require any
> additional signatures.

Thank you.  Now it makes sense to me -- a wrongdoer can insert a 
device and try booting it (e.g., the four-game-button press) -- so 
*what* he is trying to load needs to be verified for authenticity. 
Whereas the 'olpc-update' user already has a running system, and 
root privilege, so he is allowed to load.

Michael, thank you for this explanation (and for describing where 
the signatures are contained).  This is *much* clearer than the 
wiki, which gives cookbook explanations but does not say "how come".


mikus