SSL, client certs, and MITM (was WYTM?)

[Perry E. Metzger]

Ian Grigg <iang at systemics.com> writes:
> In threat analysis, you base your assessment on
> economics of what is reasonable to protect.  It
> is perfectly valid to decline to protect against
> a possible threat, if the cost thereof is too high,
> as compared against the benefits.

The cost of MITM protection is, in practice, zero. Indeed, if you
wanted to produce an alternative to TLS without MITM protection, you
would have to spend lots of time and money crafting and evaluating a
new protocol that is still reasonably secure without that
protection. One might therefore call the cost of using TLS, which may
be used for free, to be substantially lower than that of an
alternative.

How low does the risk have to get before you will be willing not just
to pay NOT to protect against it? Because that is, in practice, what
you would have to do. You would actually have to burn money to get
lower protection. The cost burden is on doing less, not on doing
more.

There is, of course, also the cost of what happens when someone MITM's
you.

You keep claiming we have to do a cost benefit analysis, but what is
the actual measurable financial benefit of paying more for less
protection?

Perry

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