Re: [Tcpcrypt] New version of the charter text

[John-Mark Gurney <[e-mail]>]

Wesley Eddy wrote this message on Thu, Apr 24, 2014 at 00:21 -0400:
> On 4/23/2014 3:02 AM, marcelo bagnulo braun wrote:
> > 
> > The TCP Inc. WG will develop the TCP extensions to provide unauthenticated
> > encryption and integrity protection of TCP streams. The WG will define the
> > TCP extensions to perform an unauthenticated key exchange resulting in
> > encryption
> > without authentication.  This is better than plain-text because it thwarts
> > passive eavesdropping, but is weaker than using authenticated keys,
> > because it
> > is vulnerable to man-in-the-middle attacks.  This work is part of the IETF
> > effort to harness the Internet architecture given the latest events of
> > pervasive
> > monitoring (see draft-farrell-perpass-attack).
> 
> 
> I'm probably just very bad at locating this in all the discussion, but
> I have a sort of fundamental question ... why are we trying to do this
> inside TCP rather than just running TCP over IPsec w/ BTNS (over UDP,
> if NAT is the concern), or over DTLS?

Have you read the original tcpcrypt paper?

> I know it's more fun to do it inside TCP, of course, but I wonder a
> little bit whether building a security sub-layer inside TCP (which
> is already hella complex and full of edge cases) is really a good
> idea when there are already a couple of reasonably decent security
> protocols designed to be layered over.
> 
> Sorry for such a silly question, but it seems like it will come up
> during chartering and should be clearly motivated, as reading the
> requirements later on in the draft charter, it looks like you could
> cook up something with BTNS or DTLS under normal TCP to do all that,
> and it would protect the SYNs (which Joe mentioned is a challenge
> for TCP-based approaches).
> 
> I think the charter should speak to this, at least very briefly.

It does very briefly:
- The protocol must be usable by unmodified applications.

All the things you mentioned seems like it would require agreement
between systems and management by a sysadmin, but this is targeted to
end users system (like smart phones) too...  If TCP is the only
protocol allowed through a firewall, how are any of your other solutions
going to work?

The goal is to make it very easy for everyone to deploy...  Configuring
IPSEC is a pain, and as Joe mentions, most implementations don't handle
key roll over properly (even though apparently, you're allowed to keep
both the old key and the new key around for the transition period to
handle this case)...

-- 
  John-Mark Gurney				Voice: [phone]

     "All that I will do, has been done, All that I have, has not."