<div dir="ltr"><div dir="ltr"><div><div class="gmail_default" style="font-family:georgia,serif;font-size:small"><font color="#000000"><b>When: </b>October 10th <b>at <span style="background-color:rgb(255,255,0)">11am CT </span></b></font></div><div><div class="gmail_default"><div dir="ltr"><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="georgia, serif"> <br><b>Where:</b><b> </b> Talk will be given<span style="background-color:rgb(255,255,0)"> </span><span style="background-color:rgb(255,255,0)"><font style="font-weight:bold"><u>live, in-person</u></font><font style="font-weight:bold"> </font></span>at</font></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="georgia, serif"> TTIC, 6045 S. Kenwood Avenue</font></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="georgia, serif"> 5th Floor, Room 530<b> </b> </font></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="georgia, serif"><br></font></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="georgia, serif" color="#000000"><b><span class="gmail_default"></span>Virtually:</b> via Panopto (<a href="https://uchicago.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=ee622f4c-8f38-431e-b637-b31a00f2af30" target="_blank">Livestream</a>) </font></p><font face="georgia, serif" color="#000000"> <br><b>Who:</b> Mahdi Haghifam, TTIC<br><br><b>Title:</b> The Sample Complexity of Membership Inference and Privacy Auditing<br><br><b>Abstract:</b> Membership Inference Attacks (MIAs) aim to determine if it is possible, using only a model's output, to distinguish training data from held-out samples. MIAs are an influential tool in machine learning privacy, with deep connections to measuring memorization, auditing differentially private algorithms, understanding generalization, and establishing fundamental privacy lower bounds. The success of these attacks often hinges on the attacker's background knowledge of the underlying data distribution. A key question of this talk is: how much knowledge about the underlying data distribution is actually necessary for an attack to succeed?<br><br>This talk makes this question precise using the language of sample complexity. We investigate a practical scenario where the attacker must learn about the data distribution from a limited number of auxiliary samples. Focusing on the fundamental setting of Gaussian mean estimation, we reveal a sharp divide based on the attacker's prior knowledge. An attacker who knows the data's covariance structure requires only a linear number of auxiliary samples to mount a successful attack. Without this knowledge, however, the required number of samples becomes at least quadratic. This result highlights that an adversary's prior knowledge is a critical factor in a model's privacy risk and has significant implications for how we design and audit private machine learning systems.<br>The talk is based on a joint work with Adam Smith and Jon Ullman and can be found at <a href="https://arxiv.org/abs/2508.19458" target="_blank">https://arxiv.org/abs/2508.19458.</a></font><p class="MsoNormal" style="margin:0in;font-family:georgia,serif;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="georgia, serif" color="#000000"><br></font></p><p class="MsoNormal" style="margin:0in;font-family:georgia,serif;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="georgia, serif" color="#000000"><br></font></p></div></div><div style="font-family:georgia,serif"><div class="gmail_default"><b><font color="#000000" face="georgia, serif">*********************************************************************************************</font></b></div><p class="MsoNormal" style="margin:0in 0in 8pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial;line-height:15.6933px"><font face="georgia, serif" color="#000000"><b>Masks are optional in all common areas. </b><b>Full visitor guidance is available at <a href="http://ttic.edu/visitors" target="_blank">ttic.edu/visitors</a>.</b></font></p><p class="MsoNormal" style="margin:0in 0in 12pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial;line-height:15.6933px"><b><font color="#000000" face="georgia, serif">*********************************************************************************************</font></b></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><b><i><font color="#000000" face="georgia, serif">Research at TTIC Seminar Series</font></i></b></p><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="georgia, serif"> </font></p><div class="gmail_default"><div dir="ltr"><div class="gmail_default"><div dir="ltr"><p class="MsoNormal" style="margin:0in;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="georgia, serif" color="#000000">TTIC is hosting a weekly seminar series presenting the research currently underway at the Institute. Every week a different TTIC faculty member will present their research. The lectures are intended for students seeking research topics and advisors, and for the general TTIC and University of Chicago communities interested in hearing what their colleagues are up to.</font></p><font color="#888888"><br></font></div><div dir="ltr" style="color:rgb(0,0,0)"><font color="#888888"><br></font></div></div></div></div></div></div><br clear="all"></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><b style="background-color:rgb(255,255,255)"><font color="#3d85c6">Brandie Jones </font></b><div><div><div><font color="#3d85c6"><b><i>Executive </i></b></font><b style="color:rgb(61,133,198)"><i>Administrative Assistant</i></b></div></div><div><b style="color:rgb(61,133,198)"><i>Outreach Administrator </i></b></div><div><span style="background-color:rgb(255,255,255)"><font color="#3d85c6">Toyota Technological Institute</font></span></div><div><span style="background-color:rgb(255,255,255)"><font color="#3d85c6">6045 S. Kenwood Avenue</font></span></div><div><span style="background-color:rgb(255,255,255)"><font color="#3d85c6">Chicago, IL 60637</font></span></div></div><div><span style="background-color:rgb(255,255,255)"><font color="#3d85c6"><a href="http://www.ttic.edu" target="_blank">www.ttic.edu</a> </font></span></div><div><span style="background-color:rgb(255,255,255)"><font color="#3d85c6"><br></font></span></div></div></div></div></div>
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