Re: [Gen-art] Genart last call review of draft-ietf-core-object-security-08

[Joel Halpern Direct <[e-mail]>]

I guess it is up to you.  Personally, I like the idea of the verify 
description including some reference to how one actually does verify.
I will leave it to the authors and WG to decide what degree of clarity 
is called for here.

Yours,
Joel

On 2/23/18 9:30 AM, Göran Selander wrote:
> Hi Joel,
> 
> Thanks for quick feedback, inline.
> 
> On 2018-02-23 14:59, "Joel M. Halpern" <[e-mail]> wrote:
> 
>> In terms of my concerns, if Step 7 said "Verify and Decrypt the COSE
>> object using the Recipient Key as per RFC 5116 Section 2.2" that would
>> fill in the confusion for this reader.
> 
> Since the AEAD is used throughout the draft, in particular in other parts
> of this section I’m thinking that maybe we should add RFC 5116 to the list
> of specifications following "Readers are expected to be familiar with” in
> Section 1.1. Would that address your comment?
> 
> Thanks
> Göran
> 
> 
> 
>>
>> Yours,
>> Joel
>>
>> On 2/23/18 5:26 AM, Göran Selander wrote:
>>> Hi Joel,
>>>
>>> Thanks for your review. Comments inline.
>>>
>>>
>>> On 2018-02-22 04:51, "Joel Halpern" <[e-mail]> wrote:
>>>
>>>> Reviewer: Joel Halpern
>>>> Review result: Ready with Nits
>>>>
>>>> I am the assigned Gen-ART reviewer for this draft. The General Area
>>>> Review Team (Gen-ART) reviews all IETF documents being processed
>>>> by the IESG for the IETF Chair.  Please treat these comments just
>>>> like any other last call comments.
>>>>
>>>> For more information, please see the FAQ at
>>>>
>>>> <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
>>>>
>>>> Document: draft-ietf-core-object-security-08
>>>> Reviewer: Joel Halpern
>>>> Review Date: 2018-02-21
>>>> IETF LC End Date: 2018-03-02
>>>> IESG Telechat date: 2018-03-08
>>>>
>>>> Summary: This document is ready for publication as a Proposed Standard
>>>> RFC
>>>>
>>>> Major issues: N/A
>>>>
>>>> Minor issues:
>>>>      In section 8.2 on verifying the request, step 5 says to "compose"
>>>> the
>>>>      Additional Authentication Data.  I would have expected it to be
>>>> "verify"
>>>>      the Additional Authentication Data.  I could imagine that the
>>>> verification
>>>>      consists of composing what it should be, and then comparing with
>>>> what
>>>> is
>>>>      received.  But I do not see the comparison step.  is it implicit in
>>>> some
>>>>      other step?  This occurs again in 8.4, so I presume I am simply
>>>> missing
>>>>      something.  This may suggest some clarification could be useful.
>>>
>>> The AAD is indeed “composed" both on encrypting and decrypting side from
>>> data which needs to be known to the endpoint at the time when the AEAD
>>> operation is performed. The authenticated decryption process is
>>> described
>>> in:
>>>
>>> https://tools.ietf.org/html/rfc5116#section-2.2
>>>
>>> So the verification consists of feeding the input, including the AAD, to
>>> the authenticated decryption which calculates the plain text or FAIL,
>>> and
>>> a failure may be - but is not necessarily - caused by wrong AAD.
>>>
>>> The AD review also indicated that we should move the reference to RFC
>>> 5116
>>> to an early section in the draft and that change is already included in
>>> the latest version on the CoRE WG Github.
>>>
>>>
>>> Best regards
>>> Göran
>>>
>