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<p class="MsoNormal"><span style="color:#1F497D">Thank you Caitlin for the compliment and the use cases below.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Apologies for the delayed reply, was out of town and did not want to mess up in a hurry.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">My thoughts inline<o:p></o:p></span></p>
<p class="MsoNormal"><span style="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"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Caitlin Bestler [mailto:Caitlin.Bestler@nexenta.com]
<br>
<b>Sent:</b> Thursday, March 07, 2013 10:37 AM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> Re: [openstack-dev] key manager proposal<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"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">Excellent proposal.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">One item not covered yet, is the possibility of running a key scope that is a collection<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">of encrypted items: for example the set of volumes and snapshots that are derived from<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">one master.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">For shallow copies, such as for volume snapshots, we could preserve the same key, and same key-id.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This does not need additional support because with volumes, Cinder on volume creation first creates a key and<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Puts it in the key-manager. Then it delegates the key to the Compute node for its retrieval.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">We could support “clone-key” in case we want to make a copy of a key but save it under a fresh key-id.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">So a snapshot could use the same key-string and key-id or<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> Same key-string and key-id-2.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">In a sense a “slightly deeper copy”, but no decrypt-re-crypt of the volume data.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The Swift replicas should they use volume encryption could be provided the same key-id or cloned-key-id.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The encryption key-id would be associated with the respective volume-ids.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">A snapshot that used the same key-id as the volume it was a snapshot of would not<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">require any copying of content to take the snapshot. Similarly if a new volume was<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">cloned from the snapshot (especially if the volume storage system supported thin<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">encoding).<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">Swift partitions could also use the same key-id on every Swift Object Server, <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">allowing rsync replication without needing to re-key/re-encrypt/whatever.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:#0070C0"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">Swift uses rsync, which is a file level protocol, (<a href="http://en.wikipedia.org/wiki/Rsync"><span style="color:#0070C0">http://en.wikipedia.org/wiki/Rsync</span></a>
</span><b><span style="color:#0070C0">rsync</span></b><span style="color:#0070C0"> is a
<a href="http://en.wikipedia.org/wiki/Utility_software" title="Utility software">
<span style="color:#0070C0">utility software</span></a> and <a href="http://en.wikipedia.org/wiki/Network_protocol" title="Network protocol">
<span style="color:#0070C0">network protocol</span></a> for <a href="http://en.wikipedia.org/wiki/Unix-like" title="Unix-like">
<span style="color:#0070C0">Unix-like</span></a> systems (with <a href="http://en.wikipedia.org/wiki/Porting" title="Porting">
<span style="color:#0070C0">ports</span></a> to <a href="http://en.wikipedia.org/wiki/Windows" title="Windows">
<span style="color:#0070C0">Windows</span></a>) that <a href="http://en.wikipedia.org/wiki/File_synchronization" title="File synchronization">
<span style="color:#0070C0">synchronizes files</span></a> and <a href="http://en.wikipedia.org/wiki/Directory_%28file_systems%29" title="Directory (file systems)">
<span style="color:#0070C0">directories</span></a> from one location to another while minimizing
<a href="http://en.wikipedia.org/wiki/Data" title="Data"><span style="color:#0070C0">data</span></a> transfer by using
<a href="http://en.wikipedia.org/wiki/Delta_encoding" title="Delta encoding"><span style="color:#0070C0">delta encoding</span></a> when appropriate.)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">So using the same volume encryption key may not buy anything.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">Should Swift one day use a block level protocol then having the same key for volume encryption would be good.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">At the file level, the encrypted object would be a bit string which would if unchanged, look exactly the same at each replication site.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">However if one of the replicas was out of synch, it would be a full file transfer because any block chaining encryption mechanism, even
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">With the exact same initialization vector would have a ripple effect beyond the point of change. With a new initialization vector, it would be a full
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0">copy.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">The critical idea here is that the scope of a key should be motivated by the need<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black">for efficient replication, snapshotting and cloning.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:black"><o:p> </o:p></span></p>
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