Re: [TLS] Proposal for hybrid solution using most of the ideas

[Nasko Oskov <noskov at microsoft.com>]

Martin Rex wrote:
>
>I'm getting slightly beaten up for "modifying the handshake message hash
>algorithm" because it is a change of the protocol and next I getting
>slightly beaten up for conveying this protocol change in through the
>ProtocolVersion server_version field.
>
>You are now proposing to put something in a list of certificates that is
>not a certificate, in a handshake message that is not sent in some of the
>handshakes to modify the message hash computation.

As far as I understand the purpose of this mailing list, it is meant to be
place for people to propose ideas and discuss them. I have proposed an idea,
it is being discussed. There are pros and cons to it. Now let's try to
either agree or disagree whether it is viable solution and move on, since we
have a problem to solve.

>Inserting the Finished messages as the first data before ClientHello into
>the handshake message hash seems problematic, because:
>
>  -    it doesn't work for scenarios where the client wants to use
>       renegotiation for client identity protection and sends the
>       next ClientHello piggy-backed on the ClientFinished message
>       of the initial handshake.

In this case it might indeed be a bit more work to implement it.

>  -    it is much more difficult for vendors/suppliers to offer
>       a backwards interop for renegotiation for whatever reason,

Backwards interop is equivalent to any other solution out there. Server will
only signal back to clients that have informed the server they are patched.
This is true for RI and your proposal for using the version number. I don't
understand why you believe it will be more difficult and there is no
specific reason you are citing. I would appreciate if you are as
constructive as in your previous point.

>if the finished messages are inserted directly following the ServerHello
>handshake messages, then these two problems don't exist.
>
>I'm going back to work on my I-D now.

Great! I'd be glad to read it.

Nasko