Hi Jim. Draft -07 now uses deterministic signing algorithms, thanks to Samuel.
Could you take another crack at reproducing the examples?
-- Mike
From: Jim Schaad [mailto:i...@augustcellars.com]
Sent: Thursday, June 22, 2017 3:09 PM
To: 'Samuel Erdtman' <sam...@erdtman.se>
Cc: draft-ietf-ace-cbor-web-to...@ietf.org; 'ace' <ace@ietf.org>
Subject: RE: [Ace] I-D Action: draft-ietf-ace-cbor-web-token-05.txt
See below.
Jim
From: Samuel Erdtman [mailto:sam...@erdtman.se]
Sent: Thursday, June 22, 2017 1:40 AM
To: Jim Schaad <i...@augustcellars.com<mailto:i...@augustcellars.com>>
Cc:
draft-ietf-ace-cbor-web-to...@ietf.org<mailto:draft-ietf-ace-cbor-web-to...@ietf.org>;
ace <ace@ietf.org<mailto:ace@ietf.org>>
Subject: Re: [Ace] I-D Action: draft-ietf-ace-cbor-web-token-05.txt
Thanks Jim!
Se comments inline
On Sun, Jun 18, 2017 at 9:21 PM, Jim Schaad
<i...@augustcellars.com<mailto:i...@augustcellars.com>> wrote:
Comments on this version of the draft.
Section 7 - Step 6 & 7 - I do not know if it is legal to have a CWT CBOR tag at
this point
In section 7.1 step 6 describes how one can add the CWT CBOR Tag to the full
CWT if transport layer cannot indicate that this is a CWT. In this case you
would want first the COSE tag and then the CWT tag this is described in section
6. We asked Carsten about this before we added the text so it should be okay.
In section 7.2 step 6 and 7 CWT CBOR tag is not mentioned as far as I can tell.
[JLS] So if an intermediary adds a layer of wrapping (i.e. encrypts it to the
end point) but the original entity who signed it put the CWT tag on it, it will
be and invalid CWT if the tag was not removed?
Appendix A.3 - I was unable to reproduce the example. I assume that this means
that a deterministic signature algorithm is not being used. While a verifier
cannot tell if one is being used, the COSE document does strongly suggest that
one be used. Additionally, it helps in testing if one is used so that a
signature creator can be more easily tested.
Correct I have not used a deterministic signing algorithm. I have used
COSE-JAVA to create the examples, is it possible to configure that
implementation to generate deterministic ECDSA signatures?
When working with my JS implementation I have noticed that support for
deterministic ECDSA implementations are hard to find.
[JLS] With COSE-JAVA, if you are using anything remotely recent is
deterministic, so that should not be a problem. I put this change into the
sources about 8 months ago. The problem may be the same issue as for A.5 where
something is different in the data to be signed.
Appendix A.5 - I was unable to reproduce the example. Specially the tag value
does not match with the one that I compute.
That is bad. but apart from the tag it looks good?
[JLS] Yes apart from the tag I matched everything – including the encryption.
This bothers me if you are using the COSE-JAVA to produce the examples. I
routinely run regression tests on both language libraries so they should
produce the same output given the same inputs. This triggers in my mind that
you might have done something odd with the external data and thus we are
generating different tags. It would be something that is being done for
signing and for encryption but not mac.
Minor:
In section 2: Is there a reason not to define CWT claim value in this section
Sorry I´m not following, could you please explain a bit more`?
[JLS] You thought it was reasonable to define a “CWT encoded claim key” in the
terms. I was just thinking that it would be symmetric to have the values have
defined here at the same time.
-----Original Message-----
From: Ace [mailto:ace-boun...@ietf.org<mailto:ace-boun...@ietf.org>] On Behalf
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Subject: [Ace] I-D Action: draft-ietf-ace-cbor-web-token-05.txt
A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Authentication and Authorization for
Constrained Environments of the IETF.
Title : CBOR Web Token (CWT)
Authors : Michael B. Jones
Erik Wahlström
Samuel Erdtman
Hannes Tschofenig
Filename : draft-ietf-ace-cbor-web-token-05.txt
Pages : 23
Date : 2017-06-05
Abstract:
CBOR Web Token (CWT) is a compact means of representing claims to be
transferred between two parties. The claims in a CWT are encoded in
the Concise Binary Object Representation (CBOR) and CBOR Object
Signing and Encryption (COSE) is used for added application layer
security protection. A claim is a piece of information asserted
about a subject and is represented as a name/value pair consisting of
a claim name and a claim value. CWT is derived from JSON Web Token
(JWT), but uses CBOR rather than JSON.
The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-ace-cbor-web-token/
There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-ace-cbor-web-token-05
https://datatracker.ietf.org/doc/html/draft-ietf-ace-cbor-web-token-05
A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-ace-cbor-web-token-05
Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at
tools.ietf.org<http://tools.ietf.org>.
Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/
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