Princeton University

School of Engineering & Applied Science

Stormy Clouds - security in distributed cloud systems

Prof. Muriel Medard
EQuad B205
Monday, April 20, 2015 - 4:30pm to 5:30pm

As massively distributed storage becomes the norm in cloud networks, they contend with new vulnerabilities imputed by the presence of data in different, possibly untrusted nodes. In this talk, we consider two such types of vulnerabilities. The first one is the risk posed to data stored at nodes that are untrusted. We show that coding alone can be substituted to encryption, with coded portions of data in trusted nodes acting as keys for coded data in untrusted ones. In general, we may interpret keys as representing the size of the list over which an adversary would need to generate guesses in order to recover the plaintext, leading to a natural connection between list decoding and secrecy. Under such a model, we show that algebraic block maximum distance separable (MDS) codes can be constructed so that lists satisfy certain secrecy criteria, which we define to generalize common perfect secrecy and weak secrecy notions. The second type of vulnerability concerns the risk of passwords’ being guessed over some nodes storing data, as illustrated by recent cloud attacks. In this domain, the use of guesswork as a metric shows that the dominant effect on vulnerability is not necessarily from a single node, but that it varies in time according to the number of guesses issued. We also introduce the notion of inscrutability, as the growth rate of the average number of probes that an attacker has to make, one at a time, using his best strategy, until he can correctly guess one or more secret strings from multiple randomly chosen strings.
Joint work with Ahmad Beirami, Joao Barros, Robert Calderbank, Mark Christiansen, Ken Duffy, Flavio du Pin Calmon, Luisa Lima, Paulo Oliveira, Stefano Tessaro, Tamas Toth, Tiago Vinhoza, Linda Zeger.
Muriel Médard is the Cecil H. Green Professor in the Electrical Engineering and Computer Science Department at MIT. She has served as editor for many IEEE publications and she is currently Editor in Chief of the IEEE Journal on Selected Areas in Communications   She was President  IEEE Information Theory Society in 2012. She has served as TPC co-chair of ISIT, WiOpt, CONEXT, and Netcod, and co-chair of ISIT and Netcod.  She was awarded the 2009 Communication Society and Information Theory Society Joint Paper Award, the 2009 William R. Bennett Prize in the Field of Communications Networking, the 2002 IEEE Leon K. Kirchmayer Prize Paper Award and several conference paper awards. She was co-winner of the MIT 2004 Harold E. Edgerton Faculty Achievement Award. In 2007 she was named a Gilbreth Lecturer by the U.S. National Academy of Engineering. She received the 2013 MIT Graduate Student Council EECS Mentor Award. In 2014 she was named by Thomson Reuters one of the World’s Most Influential Scientific Minds.