Subject: [perpass] draft-saintandre-xmpp-tls-01

From: Hannes Tschofenig <[email-masked]>
Date: Fri, 13 Sep 2013 10:35:35 +0300

Hi Peter,

I am wondering whether it would be possible to link the recommendations 
between draft-saintandre-xmpp-tls-01 and draft-sheffer-tls-bcp-00 with 
respect to what it says about TLS.

I believe that the TLS recommendations should be generic for the crypto 
(no RC4, key length, etc.) and don't depend on the specific application 
that is being protected.

Of course you could argue that it makes sense to replicate the text for 
simpler readability.

One other remark about session resumption. There are two versions of 
session resumption, namely one that is part of the base TLS spec and 
another one that provides session resumption without server side state. 
 From your text it seems that focus on the latter, which is OK.

RFC 5077 already says that you have to encrypt and authenticate the 
ticket. What can be said in the XMPP context is to implement the 
recommended format of the ticket to avoid problems with not encrypting 
the information or not authenticating it. The info is found in Section 4 
of RFC 5077. Of course, we could double-check the recommended algorithms 
for that as well.

Ciao
Hannes

---

From: Peter Saint-Andre <[email-masked]>
Date: Mon, 16 Sep 2013 15:47:10 -0600

On 9/13/13 1:35 AM, Hannes Tschofenig wrote:
> Hi Peter,
> 
> I am wondering whether it would be possible to link the
> recommendations between draft-saintandre-xmpp-tls-01 and
> draft-sheffer-tls-bcp-00 with respect to what it says about TLS.

Sure.

> I believe that the TLS recommendations should be generic for the
> crypto (no RC4, key length, etc.) and don't depend on the specific
> application that is being protected.

In general, yes. There might be some differences depending on the
application protocol that uses TLS.

> Of course you could argue that it makes sense to replicate the text
> for simpler readability.

One thing I'm trying to do with draft-saintandre-xmpp-tls is educate
and engage the XMPP community in the task of upgrading the security
profile of the XMPP network (a conversation that predates the recent
incidents).

> One other remark about session resumption. There are two versions
> of session resumption, namely one that is part of the base TLS spec
> and another one that provides session resumption without server
> side state. From your text it seems that focus on the latter, which
> is OK.
> 
> RFC 5077 already says that you have to encrypt and authenticate
> the ticket. What can be said in the XMPP context is to implement
> the recommended format of the ticket to avoid problems with not
> encrypting the information or not authenticating it. The info is
> found in Section 4 of RFC 5077. Of course, we could double-check
> the recommended algorithms for that as well.

About session resumption, I need to look more closely at RFC 5077 and
the version that is in the base spec. I am not yet fully sure that
citing RFC 5077 is the right thing for XMPP.

Peter

- -- 
Peter Saint-Andre
https://stpeter.im/