<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div>Please note that Francesca Falzon’s MS Presentation, which had been scheduled for next Thursday (April 16th), has been postponed.</div><div><br class=""></div><div>It will be rescheduled for a later date.</div><div><br class=""></div><div>------------------------------------------------------------------------------<br class="">Date: <strike class="">Thursday, April 16, 2020</strike> <— will be rescheduled for a later date<br class=""><br class="">Time: <strike class="">11:00 AM</strike><br class=""><br class="">Place: remote via Zoom <br class=""><br class="">M.S. Candidate: Francesca Falzon<br class=""><br class="">M.S. Paper Title: Multidimensional Database Reconstruction from Range<br class="">Query Access Patterns<br class=""><br class="">Abstract:<br class="">This work considers the security of systems that process encrypted<br class="">multi-dimensional range queries with only access pattern leakage.<br class="">Recent work of Kellaris et al. (CCS 2016) showed that in one<br class="">dimension, an adversary could use the access patterns of several<br class="">uniformly random range queries to reconstruct a plaintext column of<br class="">numbers ``up to reflection.'' We extend this attack to two dimensions<br class="">and find that the situation is much more complicated: Information<br class="">theoretically it is complex to describe even what is possible to<br class="">recover for the adversary in general. We provide a classification of<br class="">these limits under certain technical conditions. We also give a faster<br class="">algorithm that works for ``dense'' databases that contain at least one<br class="">record for each possible value. Finally we explore the implications<br class="">for our classification with real data sets.<br class=""><br class="">Francesca's advisor is Prof. David Cash<br class=""><br class="">Login to the Computer Science Department website for details:<br class=""> <a href="https://newtraell.cs.uchicago.edu/phd/ms_announcements#ffalzon" class="">https://newtraell.cs.uchicago.edu/phd/ms_announcements#ffalzon</a><br class=""><br class="">=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<br class="">Margaret P. Jaffey margaret at <a href="http://cs.uchicago.edu" class="">cs.uchicago.edu</a><br class="">Department of Computer Science<br class="">Student Support Rep (JCL 350) (773) 702-6011<br class="">The University of Chicago <a href="http://www.cs.uchicago.edu" class="">http://www.cs.uchicago.edu</a><br class="">=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<br class="">_______________________________________________<br class="">Colloquium mailing list - <a href="mailto:Colloquium@mailman.cs.uchicago.edu" class="">Colloquium@mailman.cs.uchicago.edu</a><br class=""><a href="https://mailman.cs.uchicago.edu/mailman/listinfo/colloquium" class="">https://mailman.cs.uchicago.edu/mailman/listinfo/colloquium</a><br class="">_______________________________________________<br class="">Phd-students mailing list<br class="">Phd-students@mailman.cs.uchicago.edu<br class="">https://mailman.cs.uchicago.edu/mailman/listinfo/phd-students<br class=""></div></body></html>