Gutmann Soundwave Therapy

[Crawford Nathan-HMGT87]

>> humans are not going to carry around large strong secrets every time
either end of the connection restarts

Which is what makes good crypto challenging.  I think, though, that
because people can understand the concept of physical locks and keys,
that this should be carried forward...

Good security is based on something you have, something you know, and
something you are.  While the third case would be rather difficult to
reliably implement on a mass-market scale, the former two are not
difficult at all.  Especially now that USB drives and CDROMs are the
defacto media standard.

Passwords do have known weaknesses - people tend to pick easily
remembered (and easily guessed) passwords.  However, when used in
combination with an external key, the security damage is at least
partially mitigated.  A system which relied on both would probably be
more secure than one which simply relied on the user entering their
password.

I've been floating the idea of selling keys on removable media.  The
core idea would be that if you get the user to use crypto keys in a
manner similar to the way they use physical keys, that you could avoid a
substantial amount of confusion, and would keep them from doing insecure
things.  You know, the typical weak password kind of thing.  If the user
has to physically plug in a USB stick for every secure session:

1.) It mitigates to a small degree the danger of key leakage because the
keys are only present on the system for small periods of time.
2.) It makes it easier for the user to use crypto - a weak password to
access the key database does not carry forward to a weak password for
session purposes.  That is, the user can have a weak key database
password without compromising the security of the underlying crypto used
for the session.

The problem is not that strong crypto is elusive, but rather, that using
it is often non-intuitive for the average user.  An unusable, or
error-prone crypto system is often worse than having none at all.


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