[Sis-dtn] [EXT] Re: SIS-DTN BPsec Profile

[Dr. Keith L Scott]

OK, that’s useful.  Yeah, if those aren’t the defaults in RFC9172 (which I suspect they’re not) then we at least have to profile 9172 in an annex of the BPsec profile to recommend those lengths.

Thx,
                                --keith

From: Mehmet Adalier <madalier at antarateknik.com>
Date: Tuesday, November 22, 2022 at 4:06 PM
To: Dr. Keith L Scott <kscott at mitre.org>, sis-dtn at mailman.ccsds.org <sis-dtn at mailman.ccsds.org>, sea-sec at mailman.ccsds.org <sea-sec at mailman.ccsds.org>
Cc: Peter Shames <peter.shames at jpl.nasa.gov>
Subject: [EXT] Re: [Sis-dtn] SIS-DTN BPsec Profile
Keith,
Not sure whether I am the “Author” on the key size comments.
Regarding algorithms/key sizes I would recommend:


  *   Integrity               SHA-384 as default
  *   Authenticity        HMAC-384 (signed hashed) as default
  *   Confidentiality   AES-CGM 256 as default

The key sizes above would be in line with the security blue/green books

v/r,
Mehmet

From: SIS-DTN <sis-dtn-bounces at mailman.ccsds.org> on behalf of "Dr. Keith L Scott via SIS-DTN" <sis-dtn at mailman.ccsds.org>
Reply-To: "Dr. Keith L Scott" <kscott at mitre.org>
Date: Tuesday, November 22, 2022 at 11:04 AM
To: "sis-dtn at mailman.ccsds.org" <sis-dtn at mailman.ccsds.org>, "sea-sec at mailman.ccsds.org" <sea-sec at mailman.ccsds.org>
Cc: Peter Shames <peter.shames at jpl.nasa.gov>
Subject: [Sis-dtn] SIS-DTN BPsec Profile

Greetings,

We have a joint meeting scheduled on Friday Dec 2.  This is nominally one of the monthly meetings to discuss the new BPsec Green Book, but I’d like to propose taking the December 2 meeting to discuss the BPsec Blue Book Profile.

I had a discussion w/ Howie the other day that resulted in a number of changes to the document:

Authenticity
Antonias had several comments around authenticity and whether or not it made any sense to provide integrity without authenticity.  I could envision a mission that wanted to provide data integrity on the science data it was returning, but might not need/want to provide authenticity.  The assumption here would be (I suppose) that it wouldn’t make sense for anyone to fake the data (e.g. a faked image purportedly from Pluto Express showing a sign on the surface “I want to be a planet again.”?)

That said, it seems like the services missions might want to choose from / implement are:

  *   Integrity
  *   Authenticity
  *   Confidentiality

[I’ll admit to being a bit confused by this; MY model for authenticity would be to use some sort of signed hash on the primary bundle block (which includes the source EID), though I suppose other mechanisms are possible].

In the document I tried to use “authenticity / integrity” where appropriate, and to otherwise mention authenticity where I thought it was appropriate.  I’d be interested if folks think I got close to right.

I still need to add some text around the ‘pick-list’ notion of integrity / authenticity / confidentiality above.

Security Contexts
I added some text about security contexts and moved other text around so that security contexts now show up earlier than they used to.

Default Security Contexts
RFC9173 contains a set of default security contexts for BPsec:

  *   Integrity Security Context BIB-HMAC-SHA2
  *   Security Context BCB-AES-GCM

I think the questions I’d like to get at at next week’s telecon is:

  *   Do we need a set of default security contexts for the CCSDS Profile of BPsec?
     *   I think so.  Maybe not even mandatory to implement but at least a defined set that can be used for testing?
  *   If the answer to the above is in fact ‘yes’ – what should we use for the default profiles?  The current book has (I think) essentially RCC9172 pulled in, but then it looks like somebody (apologies, the changes are only marked as ‘Author’) seems to have suggested changing some of the recommended key sizes.
So, if we could at least start talking about a nominal set of security contexts for the profile I think that would get us a LOT further down the road to getting the book out.

                                v/r,

                                --keith
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