Re: [IPsec] IPsec with QKD

[Greg Troxel <[e-mail]>]

<[e-mail]> writes:

> I wonder if this should be worded more generically.  This is really
> about an external key agreement mechanism.  QKD is one such mechanism,
> but it isn’t clear to me that the machinery depends on this.
> Suppose, for example, that you distributed copies of one-time pad
> CDROMs to both locations, and used the key ID as offset in the
> one-time-pad data.  This is a completely different key agreement
> scheme but it would seem to fit just as well.  The important point is
> that there is an external source of key material, which has the
> (assumed) property that the key material is known to the two endpoints
> of the IKE exchange, and to no other parties.

I agree that just having an external keying material abstraction makes
sense.   In particular, thinking about it in a larger context is likely
to force clarity on issues of how external keying material is named and
numbered, and how to deal with the possibility that bits which should
match might not.

There are multiple ways to use external material: as OTP, directly as
symmettric keys and by including it in the phase 2 hash.  We implemented
the first and third of these around 2002, and what's been published
about that system is at

  http://dx.doi.org/10.1145/863955.863982