<font size=2 face="sans-serif">Dear all,</font>
<br>
<br><font size=2 face="sans-serif">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.</font>
<br><font size=2 face="sans-serif">My take:</font>
<br><font size=2 face="sans-serif">Q1 is a typo and will be corrected.
--> No further discussion needed</font>
<br><font size=2 face="sans-serif">Q2: This should be the case. What do
the others think? Do we need to be explicit there?</font>
<br><font size=2 face="sans-serif">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?</font>
<br>
<br><font size=2 face="sans-serif">Cheers,<br>
Daniel.</font>
<br>
<br><font size=1 color=#00a1e0 face="Verdana"><b>Dr. Daniel Fischer</b></font><font size=1 color=#808080 face="Verdana"><br>
Head of the Engineering Support Section, OPS-GES<br>
Ground Systems Engineering Department</font>
<br><font size=1 color=#808080 face="Verdana">Directorate of Operations</font>
<p><font size=1 color=#808080 face="Verdana"><b>ESA - ESOC</b><br>
Robert-Bosch-Str. 5, D-64392 Darmstadt, Germany</font>
<p><font size=1 color=#808080 face="Verdana">Tel. +49 6151 90 2718 | E-mail:
Daniel.Fischer@esa.int</font>
<br><font size=1 color=#800080 face="sans-serif">----- Forwarded by Daniel
Fischer/esoc/ESA on 31/03/2017 08:51 -----</font>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">David.Koisser@esa.int</font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">sls-sea-dls@mailman.ccsds.org</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Cc:
</font><font size=1 face="sans-serif">"John P. Lucas"
<John.P.Lucas@ivv.nasa.gov></font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">01/03/2017 11:04</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">[Sls-sea-dls]
Question regarding the SDLS EP Standard</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Sent by:
</font><font size=1 face="sans-serif">"SLS-SEA-DLS"
<sls-sea-dls-bounces@mailman.ccsds.org></font>
<br>
<hr noshade>
<br>
<br>
<br><font size=2 face="Calibri">Dear SDLS WG members,</font><font size=3>
<br>
</font><font size=2 face="sans-serif"><br>
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:</font><font size=3> <br>
</font><font size=2 face="sans-serif"><br>
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:</font><font size=3> </font><font size=2 face="sans-serif"><br>
"Values 0-65535 shall not be used to reference session keys."</font><font size=3>
</font><font size=2 face="sans-serif"><br>
Which would be all possible Key IDs and leave none for any session keys.
Can you clarify?</font><font size=3> <br>
</font><font size=2 face="sans-serif"><br>
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)?</font><font size=3> <br>
</font><font size=2 face="sans-serif"><br>
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:
</font><font size=3><br>
</font><font size=2 face="sans-serif"><br>
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:</font><font size=3> </font><font size=2 face="sans-serif"><br>
GVCID = TFVN + SCID + VCID</font><font size=3> </font><font size=2 face="sans-serif"><br>
And the 2 bits long TFVN may have the following values: 01 -> AOS; 10
-> Proximity-1; 00 -> TM- *or* TC-SDLP</font><font size=3> </font><font size=2 face="sans-serif"><br>
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.</font><font size=3> <br>
</font><font size=2 face="sans-serif"><br>
Best Regards,</font><font size=3> </font><font size=2 face="sans-serif"><br>
David Koisser</font>
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