[IP] Master Key Copying Revealed (Matt Blaze of ATT Labs)

[Derek Atkins]

The fact that the hole is on the bottom pin is not important.  What is
important is that the hole at the change-key height does not need to
be at the same angular position as the hole at the master-key height.

It's hard to draw ascii art to show what I mean, but because the twist
holes are at a particular height when the key is inserted, you can
certainly see how at different heights the holes can be in different
locations.

-derek

Matt Blaze <mab at research.att.com> writes:

> Actually even in their Biaxial design the sidebar hole is always on the
> bottom pin, and so the master shares the angle with the change keys.
> 
> -matt
> 
> > There is, however, a newer medeco design that uses a drill-hole
> > instead of a groove.  With that design you can have the pin twist be
> > different at different pin-heights (by putting the drill-hole at a
> > different twist-angle).  I don't think this attack would work quite
> > as easily on this design.
> > 
> > -derek
> 

-- 
       Derek Atkins
       Computer and Internet Security Consultant
       derek at ihtfp.com             www.ihtfp.com

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