Subject: [TLS] IETF 72 - TLS Working Group Draft Minutes

From: "Joseph Salowey (jsalowey)" <[email-masked]>
Date: Thu, 31 Jul 2008 08:57:55 -0700

Below are draft minutes for the IETF-72 meeting.  Please send any
corrections or additions.  Thanks to Pratima for taking notes.  

Joe

Minutes for TLS working Group session at IETF 72
July 28, 2008 - 1520-1720 - Dublin
-----------------------------------------------
Chairs:

Joe Salowey
Eric Rescorla (on Jabber)

Notes Taker:

Pratima Sethi
-----------------------------------------------

1) TLS 1.2 status (RFC4346bis)

Joe Salowey: Handling of version mismatch in pre-master secret to avoid
side-channel attacks. Recommendation to keep the document as is.
Eric Rescorla: Mechanism described in current draft and complicated and
working is unclear. Original paper by Klima is hard to follow. He is
planning to have discussions with some cryptographers and thinks better
explanation is all that will be needed.
 
2) Extensions (RFC4366bis)

Client cert url 

Joe Salowey: current proposal to make hash extension to be made
mandatory. Other related topics - add hash agility and truncated HMAC
Yoav Nir: Extension never been used in IKE or TLS and hence changes can
be made.
Eric: mentions that the issue was raised by NIST and Tim can comment on
it.  Tim not present.
Pasi: clarifies NIST -- after you run the authentication protocol,
parties would know who the peers are, and this isn't clear without the
hash.  Hence the need for hash inclusion.
Joe:  Hash agility can be added in a backward compatible way.
Joe: show of hands for making hash mandatory shows a preference for
making the hash mandatory w/o need of a new extension
4 for making existing hash mandatory 0 for new extension

Take it too the list

Pasi: Slide should not be about truncated hash but about max fragment
length. (fix in slide)

3) cipher suite status

Joe: Several drafts waiting on TLS 1.2
Badra: New Version submitted for EDCHE draft just before meeting
Comment from jabber: Is there expired draft on ghost(?) cipher suites.
Joe: Not sure what the status of the document is, it expired a while
ago. 

4) DTLS update (rfc4347bis)

Abhijit Choudhury: Queries group about thoughts on aligning headers on
word boundaries. Abhijit comments that unaligned headers increases die
sizes on ASICs and this has been a historical problem inherited from
TLS.
Joe: so the problem is it requires more silicon to achieve the same
speed. 
Joe: This change may be too big to include in DTLS 1.2 and preferable to
discuss some more.  Perhaps is possible to have a solution for TLS and
DTLS.  
 
5) TLS Key Generation  
draft-urien-tls-keygen-00 
<presentation by Pascal Urien> 

Joe: what is different about this than TLS extractor
Pascal: difference with tls-extractor which uses a TLS PRF function is
used and secondly the use case where server pushes the key which is not
addressed by tls-extractor. 
Joe: why not use the same PRF ? 
Pascal: Is the same PRF function well suited for everything?
Eric: What is the use case of this draft 
Pascal: for applications outside TLS or on top of TLS. A) Outside TLS
for protocols like BGP ( peer to peer mode) or Push TV( server)
Eric: applications for usage of keys outside of TLS is out of scope of
this Working Group
Pasi Eronen(AD): agrees.
Joe: Agrees with Eric and Pasi's comments and recommends. If we are
going pursue something like this, it should tie into the extractor draft
as the extractor draft is going to be the default way of extracting keys
from TLS.
Bob Morgan:  What type of implementation have you done 
Pascal: implemented what is in the draft, could be applied to many
different things 

6) Camellia cipher suites for TLS.
draft-kato-tls-rfc4132bis-02
<presentation by Satoru Kannu>
Joe: This may be better as an individual submission since it is only
changing an encryption algorithm.  

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