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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Paulo,<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 style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I believe you’ll find that we’re thinking along the same lines. Please review my proposal at
</span><a href="http://etherpad.openstack.org/P9MMYSWE6U">http://etherpad.openstack.org/P9MMYSWE6U</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">One quick observation is that SHA-1 is totally inadequate for fingerprinting objects in a public object store. An attacker could easily<o:p></o:p></p>
<p class="MsoNormal">predict the fingerprint of content likely to be posted, generate alternate content that had the same SHA-1 fingerprint and pre-empt<o:p></o:p></p>
<p class="MsoNormal">the signature. For example: an ISO of an open source OS distribution. If I get my false content with the same fingerprint into the<o:p></o:p></p>
<p class="MsoNormal">repository first then everyone who downloads that ISO will get my altered copy.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">SHA-256 is really needed to make this type of attack infeasible.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I also think that distributed deduplication works very well with object versioning. Your comments on the proposal cited above
<o:p></o:p></p>
<p class="MsoNormal">would be great to hear.<span 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"><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""> openstack-bounces+caitlin.bestler=nexenta.com@lists.launchpad.net [mailto:openstack-bounces+caitlin.bestler=nexenta.com@lists.launchpad.net]
<b>On Behalf Of </b>Paulo Ricardo Motta Gomes<br>
<b>Sent:</b> Thursday, March 08, 2012 1:19 PM<br>
<b>To:</b> openstack@lists.launchpad.net<br>
<b>Subject:</b> [Openstack] Enabling data deduplication on Swift<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hello everyone,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'm a student of the European Master in Distributed Computing (EMDC) currently working on my master thesis on distributed content-addressable storage/deduplication.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'm happy to announce I will be contributing the outcome of my thesis work to OpenStack by enabling both object-level and block-level deduplication functionality on Swift (<a href="https://answers.launchpad.net/swift/+question/156862">https://answers.launchpad.net/swift/+question/156862</a>).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I have written a detailed blog post where I describe the initial architecture of my solution: <a href="http://paulormg.com/2012/03/05/enabling-deduplication-in-a-distributed-object-storage/">http://paulormg.com/2012/03/05/enabling-deduplication-in-a-distributed-object-storage/</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Feedback from the OpenStack/Swift community would be very appreciated.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Cheers,<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Paulo<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <br>
European Master in Distributed Computing - <a href="http://www.kth.se/emdc" target="_blank">
www.kth.se/emdc</a><span style="font-family:"Arial","sans-serif""><br>
Royal Institute of Technology - KTH</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif"">Instituto Superior Técnico - IST</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif""><a href="http://paulormg.com" target="_blank">http://paulormg.com</a></span><o:p></o:p></p>
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