Subject: [Dtls-iot] Fwd: [dice] #7 (profile): Truncated MAC extension

From: Hannes Tschofenig <[email-masked]>
Date: Sat, 21 Jun 2014 20:19:47 +0200

-------- Original Message --------
Subject: [dice] #7 (profile): Truncated MAC extension
Date: Fri, 20 Jun 2014 15:15:33 -0000
From: dice issue tracker <[email-masked]>
To: [email-masked]
CC: [email-masked]

#7: Truncated MAC extension

 This extension reduces the size of the MAC at the Record Layer. This is a
 useful extension for those environments where TLS ciphersuites use older
 modes of operation.

 For CoAP, however, the recommended ciphersuites use the AEAD construct,
 namely the CBC-MAC mode (CCM) with eight-octet authentication tags.

 Recommendation: This extension does not add any value given the CoAP
 selected ciphersuites. Recommend against supporting it.

-- 
---------------------------------------+-------------------------------
 Reporter:  [email-masked]  |      Owner:  Hannes Tschofenig
     Type:  defect                     |     Status:  new
 Priority:  major                      |  Milestone:
Component:  profile                    |    Version:
 Severity:  Active WG Document         |   Keywords:
---------------------------------------+-------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/dice/trac/ticket/7>
dice <http://tools.ietf.org/dice/>

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From: Russ Housley <[email-masked]>
Date: Sat, 21 Jun 2014 15:36:45 -0400

I agree with this recommendation if and only if the profile clearly states that it only supports AEAD ciphersuites.

Russ

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From: Hannes Tschofenig <[email-masked]>
Date: Sun, 22 Jun 2014 09:33:03 +0200

Hi Russ,

This additional qualification makes sense to me. I also don't think we
are too restrictive with the focus on AEAD ciphersuites for the use
cases we are talking about.

Ciao
Hannes