[Sls-sea-dls] Fw: Question regarding the SDLS EP Standard

Tue Apr 11 17:32:49 UTC 2017

If you do that first thing on friday am somebody from sdls may be able to attend too. 

Sent from my iPhone

> On 11 Apr 2017, at 18:37, Kazz, Greg J (312B) <greg.j.kazz at jpl.nasa.gov> wrote:
> 
> I think it is a good proposal and it is a topic we will address during the SLP WG meeting on Friday AM and perhaps also it could be discussed during the SDLS meeting on Wed.
> However, we don’t have a SLS area joint meeting scheduled in San Antonio.
> Perhaps we could take some time on Friday afternoon in the SLS plenary to come up with a joint way forward based upon the discussions in those other two forums.
>  
> G.P. – what do you think?
>  
> Thanks!
> Greg
>  
> From: Moury Gilles <Gilles.Moury at cnes.fr>
> Date: Tuesday, April 11, 2017 at 4:08 AM
> To: "Daniel.Fischer at esa.int" <Daniel.Fischer at esa.int>, "Greenberg, Edward (312B)" <edward.greenberg at jpl.nasa.gov>
> Cc: Greg Kazz <greg.j.kazz at jpl.nasa.gov>, "sls-sea-dls at mailman.ccsds.org" <sls-sea-dls at mailman.ccsds.org>, Calzolari Gian-Paolo <Gian.Paolo.Calzolari at esa.int>
> Subject: RE: [Sls-sea-dls] Fw: Question regarding the SDLS EP Standard
>  
> Dear Ed,
>  
> I tend to agree with Daniel : this problem of GVCID ambiguity for bidirectional spacelinks is a general problem that will be encountered not only by SDLS EP (for SA management procedures) but also for all bidirectional protocols like AOS, USLP for which GVCID does not carry the direction (forward or return) of the VC we are dealing with. The solution you propose to introduce 2 new IDs (GVCIDS, GVCIDR) would solve the ambiguity but needs to be agreed SLS-wide. Greg and Gian-Paolo: what is your opinion ?
>  
> Best regards,
>  
> Gilles
>  
> Gilles MOURY 
> CNES Toulouse
> De : Daniel.Fischer at esa.int [mailto:Daniel.Fischer at esa.int] 
> Envoyé : mardi 11 avril 2017 12:32
> À : Greenberg, Edward (312B)
> Cc : Moury Gilles; Kazz, Greg J (312B); sls-sea-dls at mailman.ccsds.org
> Objet : RE: [Sls-sea-dls] Fw: Question regarding the SDLS EP Standard
>  
> Dear Ed, 
> 
> Sorry for not coming back to you earlier. I think we will discuss your recommendation in the upcoming meetings. 
> In my opinion the scope of the impact of the new definitions of the GVCIDR/S is not limited to SDLS or SDLS Extended Procedures and needs to be discussed in a wider frame. 
> 
> Cheers, 
> Daniel 
> 
> Dr. Daniel Fischer
> Head of the Engineering Support Section, OPS-GES
> Ground Systems Engineering Department 
> Directorate of Operations
> ESA - ESOC
> Robert-Bosch-Str. 5, D-64392 Darmstadt, Germany
> 
> Tel. +49 6151 90 2718 |  E-mail: Daniel.Fischer at esa.int 
> 
> 
> 
> From:        "Greenberg, Edward (312B)" <edward.greenberg at jpl.nasa.gov> 
> To:        Moury Gilles <Gilles.Moury at cnes.fr>, "Daniel.Fischer at esa.int" <Daniel.Fischer at esa.int>, "sls-sea-dls at mailman.ccsds.org" <sls-sea-dls at mailman.ccsds.org> 
> Cc:        "Kazz, Greg J (312B)" <greg.j.kazz at jpl.nasa.gov> 
> Date:        11/04/2017 01:36 
> Subject:        RE: [Sls-sea-dls] Fw:  Question regarding the SDLS EP Standard
> 
> 
> 
> 
> I never had a response to my recommendation.  I made this recommendation for compatibility with AOS, proximity 1 and USLP since these protocols can be used in both directions thus the PVN is not a discriminator.   TM and TC have a 2 bit PVN and they are both ‘00’.   
>   
> From: Greenberg, Edward (312B) 
> Sent: Friday, March 31, 2017 2:24 PM
> To: 'Moury Gilles'; Daniel.Fischer at esa.int; sls-sea-dls at mailman.ccsds.org
> Subject: RE: [Sls-sea-dls] Fw: Question regarding the SDLS EP Standard 
>   
> The SCID identifies the Spacecraft.  The SOURCE/DESTINATION FLAG identifies the sending side or the receiving side.  Thus by including the SOURCE/DESTINATION FLAG into the GVCID/GMAPID you determine the sending side GVCID verses the receiving side GVCID.  By simply modifying the term GVCID to GVCIDS for the sending side and GVCIDR for the receiving side you separate the VCs by directionality which is exactly what you want.   
>   
> From: SLS-SEA-DLS [mailto:sls-sea-dls-bounces at mailman.ccsds.org] On Behalf Of Moury Gilles
> Sent: Friday, March 31, 2017 2:00 AM
> To: Daniel.Fischer at esa.int; sls-sea-dls at mailman.ccsds.org
> Subject: Re: [Sls-sea-dls] Fw: Question regarding the SDLS EP Standard 
>   
> Dear all, 
>   
> My response to David’s questions would be : 
>   
> Q1 : values 0 and 65535 are reserved (for master keys I understand). Text should be modified. 
>   
> Q2 : EP baseline mode relies on SDLS baseline mode. SDLS baseline mode uses AES-GCM. In that case, the SN is replaced by the IV which is 96 bits. Therefore, the Set ARC procedure of the EP baseline mode is actually setting the IV. I would recommend adding this clarification in the EP baseline mode specification and changing the length of the “New anti-replay counter value” field from 64 to 96 bits for consistency with SDLS baseline mode. 
>   
> Q3 : My proposal would be the following: 
> ·        For the EP baseline mode, a format is specified for the GVCID/GMAPID field of the  Start SA PDU with the following sub-fields: 
> o   TFVN (4 bits) 
> o   SCID (16 bits) 
> o   VCID (6 bits) 
> o   MAPID (6bits) 
> ·        Since we have specified TFVN sub-field length as 4 bits, we have 2 spare bits there. We could use one of them to distinguish TC from TM : ‘000’ would code for TC TFVN and ‘100’ would code for TM TFVN, while ‘001’ would code for AOS and ‘010’ for Prox-1 (which is not covered by SDLS by the way). 
>   
> Best regards, 
> Gilles 
>   
>   
>   
> Gilles MOURY 
> CNES Toulouse 
> De : SLS-SEA-DLS [mailto:sls-sea-dls-bounces at mailman.ccsds.org] De la part de Daniel.Fischer at esa.int
> Envoyé : vendredi 31 mars 2017 08:57
> À : sls-sea-dls at mailman.ccsds.org
> Objet : [Sls-sea-dls] Fw: Question regarding the SDLS EP Standard 
>   
> Dear all, 
> 
> Could ask you to take a look at the questions that David sent a while go...some of them need answers before a red book can be produced. 
> My take: 
> Q1 is a typo and will be corrected. --> No further discussion needed 
> Q2: This should be the case. What do the others think? Do we need to be explicit there? 
> Q3: This is a critical one and we don't have an answer at the moment. I remember we discussed this in the WG already but I am not sure we came to a conclusion. This needs to be clarified in the standard. Any opinions? 
> 
> Cheers,
> Daniel. 
> 
> Dr. Daniel Fischer
> Head of the Engineering Support Section, OPS-GES
> Ground Systems Engineering Department 
> Directorate of Operations
> ESA - ESOC
> Robert-Bosch-Str. 5, D-64392 Darmstadt, Germany
> 
> Tel. +49 6151 90 2718 |  E-mail: Daniel.Fischer at esa.int 
> ----- Forwarded by Daniel Fischer/esoc/ESA on 31/03/2017 08:51 ----- 
> 
> From:        David.Koisser at esa.int 
> To:        sls-sea-dls at mailman.ccsds.org 
> Cc:        "John P. Lucas" <John.P.Lucas at ivv.nasa.gov> 
> Date:        01/03/2017 11:04 
> Subject:        [Sls-sea-dls] Question regarding the SDLS EP Standard 
> Sent by:        "SLS-SEA-DLS" <sls-sea-dls-bounces at mailman.ccsds.org>
> 
> 
> 
> 
> 
> Dear SDLS WG members, 
> 
> John and I have completed setting up the interoperability testing environment and now we are doing a few finishing touches. Whilst doing this a few questions arose regarding the SDLS EP standard: 
> 
> 1. In Section E4.2.2 (in the baseline mode description of Key Activation) and the following key procedures, it defines the Key ID fields to have a length of 16 bits. And then states: 
> "Values 0-65535 shall not be used to reference session keys." 
> Which would be all possible Key IDs and leave none for any session keys. Can you clarify? 
> 
> 2. While we are fairly sure it is implied: Does the M&C procedure Set ARC set the IV instead of the SN parameter in the regarding cases (e.g. AES-GCM)? 
> 
> 3. The standard is not addressing how to distinguish if a GVCID is regarding the TM or TC channels for the Start SA procedure. An example to clarify: 
> 
> A mission wants a different SA assigned on VC 0 for the uplink (e.g. authentication only) than the VC 0 for the downlink (e.g. authenticated encryption). To be able to set this with the Start SA procedure, it needs a way to distinguish between the TC and TM channel mapping to SPIs. As the GVCID is defined as: 
> GVCID = TFVN + SCID + VCID 
> And the 2 bits long TFVN may have the following values: 01 -> AOS; 10 -> Proximity-1; 00 -> TM- *or* TC-SDLP 
> The GVCID alone is not enough to distinguish between TC and TM and we are currently using a custom data structure for unambiguously identifying the channels in the Start SA procedure. 
> 
> Best Regards, 
> David Koisser 
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