Ilari,
Thanks for confirming this. It does appear that the section on AES-KW in RFC 
9053 [2] includes the statement "The protected header bucket MUST be empty." 
and two families defined in RFC 9459 [3] have similar statements. But the 
direct (-6) algorithm makes no such statement nor does the RSAES-OAEP family 
[4]. So it seems desirable but inconsistent.

Does this rise to the level of an errata for the general discussion of 
protected header in RFC 9052? I think having specific guidance there would help 
understanding for those who don't have a huge background in this ecosystem.

Brian S.

[2] https://www.rfc-editor.org/rfc/rfc9053.html#section-6.2.1
[3] https://www.rfc-editor.org/rfc/rfc9459.html
[4] https://www.rfc-editor.org/rfc/rfc8230.html#section-3

> -----Original Message-----
> From: [email protected] <[email protected]>
> Sent: Thursday, July 3, 2025 3:17 PM
> To: [email protected]
> Subject: [EXT] [COSE] Re: Requirement for protected header to actually be
> protected
> 
> APL external email warning: Verify sender [email protected] before
> clicking links or attachments
> 
> On Thu, Jul 03, 2025 at 05:48:21PM +0000, Sipos, Brian J. wrote:
> > WG,
> >
> > I was looking for, and have failed to find, any requirement in the
> > base COSE specification [1] that if the protected header map is
> > non-empty the associated algorithm must support additional
> > authenticated data (AAD). The non-normative text and examples seem to
> > support this but I don't see anything normative around this. Am I just
> > missing something? Or does this seem like something that deserves a
> constraint?
> >
> 
> I guess this was what was intended — like intending to only have authenticated
> symmetric encryption so to not need algorithm binding — but it wasn't 
> explicitly
> written anywhere. The section on AE certainly forbids protected headers.
> 
> 
> 
> 
> -Ilari
> 
> _______________________________________________
> COSE mailing list -- [email protected]
> To unsubscribe send an email to [email protected]

Attachment: smime.p7s
Description: S/MIME cryptographic signature

_______________________________________________
COSE mailing list -- [email protected]
To unsubscribe send an email to [email protected]

Reply via email to