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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Shall we adopt Bruno’s proposal ? In that case, we probably do not need the challenge-response transaction.<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:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Gilles MOURY</span><span lang="EN-US" style="color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">CNES Toulouse</span><span lang="EN-US" style="color:#1F497D">
</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">De :</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> sls-sea-dls-bounces@mailman.ccsds.org [mailto:sls-sea-dls-bounces@mailman.ccsds.org]
<b>De la part de</b> Weiss, Howard<br>
<b>Envoyé :</b> lundi 18 avril 2016 19:27<br>
<b>À :</b> Saba Bruno; Daniel.Fischer@esa.int; sls-sea-dls@mailman.ccsds.org<br>
<b>Objet :</b> RE: [Sls-sea-dls] Key Verification using CRC<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">I agree with Bruno.<br>
<br>
Howie<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">Howard Weiss</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black"><br>
</span><span style="font-size:7.5pt;font-family:"Tahoma","sans-serif";color:black">Technical Director</span><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black"><br>
<br>
<b>PARSONS</b></span><span style="font-size:7.5pt;font-family:"Tahoma","sans-serif";color:black"><br>
7110 Samuel Morse Drive<br>
Columbia, MD 21046<br>
443-430-8089 (office)<br>
410-262-1479 (cell)<br>
443-430-8238 (fax)<br>
<a href="mailto:howard.weiss@parsons.com">howard.weiss@parsons.com</a><br>
<a href="http://www.parsons.com">www.parsons.com</a><br>
<br>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">
<a href="mailto:sls-sea-dls-bounces@mailman.ccsds.org">sls-sea-dls-bounces@mailman.ccsds.org</a> [sls-sea-dls-bounces@mailman.ccsds.org] on behalf of Saba Bruno [Bruno.Saba@cnes.fr]<br>
<b>Sent:</b> Monday, April 18, 2016 9:48 AM<br>
<b>To:</b> <a href="mailto:Daniel.Fischer@esa.int">Daniel.Fischer@esa.int</a>; <a href="mailto:sls-sea-dls@mailman.ccsds.org">
sls-sea-dls@mailman.ccsds.org</a><br>
<b>Subject:</b> RE: [Sls-sea-dls] Key Verification using CRC</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dear all,</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><span style="color:black"><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">One solution to avoid the use of a challenge-response system and stay with the simple CRC for on-board key checking is to compute the CRC on BOTH
the Key-ID and the key itself.</span><span style="color:black"><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"> </span><span style="color:black"><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">Ideally, what we know as a “key” would be a “Meta-Key”, comprising :</span><span style="color:black"><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"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-</span><span lang="EN-US" style="font-size:7.0pt;color:#1F497D">
</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The Key ID, unique identifier of the key for the whole mission duration,</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-</span><span lang="EN-US" style="font-size:7.0pt;color:#1F497D">
</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The Key itself (secret random data)</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-</span><span lang="EN-US" style="font-size:7.0pt;color:#1F497D">
</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The CRC, computed on the Key ID and the key itself.</span><span style="color:black"><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"> </span><span style="color:black"><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">This “Meta-Key” should be considered as an single entity, not splittable, being stored, transferred and distributed as is (on-board AND at ground
level, from generation to destruction).</span><span style="color:black"><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"> </span><span style="color:black"><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">Cheers,</span><span style="color:black"><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"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Bruno Saba</span><span lang="EN-US" style="color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">CNES</span><span lang="EN-US" style="color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">DCT/TV/IN</span><span lang="EN-US" style="color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">18 Avenue Edouard Belin</span><span lang="EN-US" style="color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">31401 TOULOUSE Cedex 9</span><span lang="EN-US" style="color:#1F497D">
</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Tel : + 33 (0) 5 61 28 28 76</span><span style="color:#1F497D">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Fax : + 33 (0) 5 61 28 19 96</span><span style="color:#1F497D">
</span><span style="color:black"><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"> </span><span style="color:black"><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"> </span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">De :</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">
<a href="mailto:sls-sea-dls-bounces@mailman.ccsds.org">sls-sea-dls-bounces@mailman.ccsds.org</a> [<a href="mailto:sls-sea-dls-bounces@mailman.ccsds.org">mailto:sls-sea-dls-bounces@mailman.ccsds.org</a>]
<b>De la part de</b> <a href="mailto:Daniel.Fischer@esa.int">Daniel.Fischer@esa.int</a><br>
<b>Envoyé :</b> dimanche 17 avril 2016 13:13<br>
<b>À :</b> <a href="mailto:sls-sea-dls@mailman.ccsds.org">sls-sea-dls@mailman.ccsds.org</a><br>
<b>Objet :</b> [Sls-sea-dls] Key Verification using CRC</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Dear all,</span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">I was discussing our new approach to key verification using the onboard-stored CRCs with David,</span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">He came up with a keen observation. </span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">The CRC-based key verification is somewhat weaker than one based on a challenge-response. The reason is that the CRC ensues you that the key at a certain slot is still OK in
terms of integrity. In contrast to the challenge-response approach it DOES NOT tell you that the key is the same as the key with same key ID on ground.</span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Is this an issue for us? What do you think? The only way we have to check key synchronisation is to use a key for actual traffic protection and see if it works.</span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">What do you think?</span><span style="color:black">
<br>
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Cheers</span><span style="color:black">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Daniel</span><span style="color:black">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black"><br>
<br>
<br>
<br>
Dr. Daniel Fischer<br>
----------------------------<br>
Data Systems Manager<br>
Ground Segment Engineering Support Office (OPS-GE)<br>
Ground Systems Engineering Department<br>
Directorate of Operations<br>
<br>
European Space Agency - ESOC<br>
Robert-Bosch-Str. 5<br>
D-64293 Darmstadt - Germany<br>
Tel: +49 (0) 6151 90 2718 - Fax: +49 (0) 6151 90 2718<br>
Web: </span><span style="color:black"><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.esa.int_&d=BQMFAw&c=Nwf-pp4xtYRe0sCRVM8_LWH54joYF7EKmrYIdfxIq10&r=dT3K0y3n0RD9-56k-UVMPMP98PIQRd2Kzfa-AwqQOww&m=KmN17nxUMzCwV8w34kOrcf_v-AiSW05d3ZrGT3WEwEk&s=mA6vGF_WMAaO1e4I2x3Pnor6OGmfWEXhPWqN5MXu0eE&e=" target="_blank"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">http://www.esa.int</span>[esa.int]</a><o:p></o:p></span></p>
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