Re: [TLS] CCS and key reset and renegotiation

[Peter Gutmann <[e-mail]>]

"Salz, Rich" <[e-mail]> writes:

>I wasn't suggesting a set of ladders to replace a state machine.  Peter said
>it's not really a state machine but rather a ladder. I was emphasizing that,
>*if this is true*, then a ladder approach is way much better.

So I did some simple diagrams for SSL years and years ago, see page 10 of
https://www.cs.auckland.ac.nz/~pgut001/pubs/app_sec.pdf.  I didn't include
renegotiation because my code doesn't do it (I'd always seen it as a problem,
not a solution) and optional add-ons like client cert auth which can easily be
added.  The whole thing is so obviously a ladder that I never understood why
the RFC tried to make it a state machine.

(Interestingly, the same page also contains the SSH protocol as a ladder
diagram.  SSH does more or less the same thing as TLS, only a lot more
awkwardly, and they don't try and present the protocol as a state machine.
Mind you they don't do it as a ladder diagram either without a lot of digging
in the text "both sides send X, then once X has been sent they go on to Y,
then once that's done they do Z, ...").

Peter.