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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hello David,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Thank you for those remarks/issues on the EP draft. Please find hereafter my proposals/remarks on the points you raised:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif">- The Rekey SA has two possible PDUs under the same Tag (TC case and TM case): This makes processing ambiguous without looking up the SPI as well as its assigned channels OR implying
from the length field. </span><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Further, it is not clear why the TM version still needs two Key-IDs as well as both IV and ARSN (doesn't USLP also work with AES-GCM?).</span>
<br>
<span style="font-size:10.0pt;font-family:"Arial",sans-serif">--> Suggestion: Two PDUs with the same structure, e.g., TC: SPI, Auth-Key, ARSN (96 Bit with padding) and TM: SPI, Encr-Key, IV.(OR all four fields for both)</span>
<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I agree that for TM, AOS and USLP we need only one key and an IV since the associated SDLS baseline mode is AES-GCM which requires only one key for
authenticated encryption and an IV (96-bit). We could simplify the format of the “Rekey SA Command PDU for TM, AOS, and USLP” to reflect that. As for merging the 2 PDUs (TC, TM/AOS/USLP) into one single format, I would prefer staying with two so that the TC
PDU remains as short as possible.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif">- The Read ARSN also has two possible PDUs under the same Tag.</span><span lang="EN-US">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif">--> Suggestion: Making the ARSN field 96 Bits (with padding).</span><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Same remark as for the Rekey SA procedure, I would prefer staying with two so that the TC PDU remains as short as possible.</span><span lang="EN-US"><br>
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif">- The Start SA PDU only shows one Tag: The third Tag field can be either '01' or '10', depending on up- or downlink.
</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif">(also, there can be no mix between both types of GVCIDs)</span>
<br>
<span style="font-size:10.0pt;font-family:"Arial",sans-serif">--> Suggestion: State that the Tag changes when addressing downlink.</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I support your suggestion. We could add a sentence/note in §5.5.1.1. Overview (of SA Management Procedures) and in § D.5 Overview (of SA Management
Procedures – baseline mode) stating :<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">“All PDU format figures in §5.5 (or § D.5) show a Service Group field setting of ‘01’ indicating an SA Management Procedure
targeting SAs that handle communication from the Initiator to the Recipient (see §5.3.2.2.2.3). It should be noted that a Service Group field setting of ‘10’ is to be used when the SA Management procedure targets an SA that handle communication from the Recipient
to the Initiator. </span><span lang="EN-US"><br>
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif">- The Read ARSN Reply PDU has no SPI: This makes the procedure implicitly stateful, meaning it cannot be interpreted on its own and on multiple requests the order must be considered.</span><span lang="EN-US">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif">--> Suggestion: Include the SPI as well.</span>
<span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Including the SPI in the response PDU would make it self-standing and unambiguous.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">We have scheduled a webex telcon on July 18 16:00 CEST to finalize the EP blue book before sending it to CCSDS Secretariat for further publication.
We will have to take a decision wrt those modifications before or at the telcon.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Gilles<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Gilles MOURY<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">CNES Toulouse<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
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