[Cryptography] nuclear arming codes

[Peter Fairbrother]

On 03/01/14 16:57, Watson Ladd wrote:

> For the arms control treaties they use statistical methods AFAIK.


One technique I'm told is still in use is to affix glitter in random 
patterns in clear epoxy to missile and/or warhead parts, then shine 
lights on it from variable positions and compare the return sparkle 
images to a known set for that patch. Very hard to forge.

Typically used to uniquely identify missile parts with a view to 
counting them, with a friendly guy shining the lights in situ, in some 
circumstances it can also be used with an enemy guy shining the lights 
in a remote challenge-response fashion to ensure that the patch is still 
intact - eg break the glass substrate which locks the core in its silo 
and you break the patch.


-- Peter Fairbrother