June 2018 - talks - lists.cs.princeton.edu

Steven Englehardt will present his FPO "Automated discovery of privacy violations on the web" on Friday, 6/29/2018 at 10:00am in CS 402.
by Nicki Gotsis 20 Jun '18

20 Jun '18

Steven Englehardt will present his FPO "Automated discovery of privacy violations on the web" on Friday, 6/29/2018 at 10:00am, 402 Computer Science. All are welcome to attend. The members of his committee are as follows: Examiners: Arvind Narayanan (Adviser), Prateek Mittal (ELE), and Jennifer Rexford; Readers: Ed Felten, Nick Feamster Abstract follows below. Tracking protection provided by browsers is often ine↵ective, while solutions based on voluntary cooperation, such as Do Not Track, haven’t had meaningful adoption. Knowledgeable users may turn to anti-tracking tools for protection, but we find that even these more advanced solutions fail to fully protect against the techniques we study. In this dissertation, we introduce OpenWPM, a platform we developed for flexible and modular web measurement. We’ve used OpenWPM to run large-scale studies leading to the discovery of numerous privacy and security violations across the web and in emails. These discoveries have curtailed the adoption of tracking techniques, and have informed policy debates and browser privacy decisions. In particular, we present novel detection methods and results for persistent tracking techniques, including: device fingerprinting, cookie syncing, and cookie respawning. Our findings include sophisticated fingerprinting techniques never before measured in the wild. We’ve found that nearly every new API is misused by trackers for fingerprinting. The misuse is often invisible to users and publishers alike, and in many cases was not anticipated by API designers. We take a critical look at how the API design process can be changed to prevent such misuse in the future. We also explore the industry of trackers which use PII-derived identifiers to track users across devices, and even into the o✏ine world. To measure these techniques, we develop a novel bait technique, which allows us to spoof the presence of PII on a large number of sites. We show how trackers exfiltrate the spoofed PII through the abuse of browser features. We find that PII collection is not limited to the web—the act of viewing an email also leaks PII to trackers. Overall, about 30% of emails leak the recipient’s email address to one or more third parties. Finally, we study the ability of a passive eavesdropper to leverage tracking cookies for mass surveillance. If two web pages embed the same tracker, then the adversary can link visits to those pages from the same user even if the user’s IP address varies. We find that the adversary can reconstruct 62—73% of a typical user’s browsing history

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Jieming Mao FPO Thursday June 14, 2018 10:00 CS 402
by Barbara A. Mooring 14 Jun '18

14 Jun '18

Jieming Mao will present his FPO on Thursday June 14, 2018 at 10:00 in room CS 402. Committee: Mark Braverman, Adviser - Princeton University Elad Hazan - Princeton University Ran Raz - Princeton University All are welcomed to attend. Title: Algorithms in Strategic or Noisy Environments Abstract: Algorithms are often used to interact with agents. When the input is collected from agents instead of being directly given, designing algorithms becomes more challenging. Two main challenges arise here: (i) agents may lie to maximize their own utility functions and we need to take their incentives into account (ii) the uncertainty in agents' behavior makes the input appear to be noisy. In this thesis, we study these two challenges in several contexts: the multi-armed bandit problem, combinatorial auctions and rank aggregation. Our goal is to understand how these strategic and noisy factors make the problem harder and to design new techniques which make algorithms robust against these factors. In Part I (Chapter 2 and Chapter 3), we study multi-armed bandit algorithms in strategic environments where rewards are decided by actions taken by strategic agents. We show that traditional multi-armed bandit algorithms could fail and we also develop multi-armed bandit algorithms which achieve good performance in strategic envrionments. In Part II (Chapter 4 and Chapter 5), we focus on combinatorial auctions which are a natural testbed for truthful mechanisms. We characterize the power of truthful mechanisms in several settings and make progress in understanding whether truthful mechanisms are as powerful as algorithms. In Part III (Chapter 6, Chapter 7 and Chapter 8), we study the top-k ranking problem. In this problem, even if the agents are perfectly incentivized, their reported comparison results could still be noisy caused by reasons like limit of knowledge and subjective preferences. We design algorithms which aggregate noisy comparisons to output the set of top items. Barbara A. Mooring Interim Graduate Coordinator Computer Science Department Princeton University

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Sivakanth Gopi FPO June 11, 2018 10:00 am CS 402
by Barbara A. Mooring 08 Jun '18

08 Jun '18

Sivakanth Gopi will present his FPO on June 11, 2018 at 10:00 am in room CS 402. All are welcomed to attend. Committee: Zeev Dvir, Adviser - Princeton University Ran Raz - Princeton University Avi Wigderson - Institute for Advanced Study Title: Locality in Coding Theory Abstract: Error correcting codes have been extremely successful in practice to build storage and communication systems which are resilient to noise and corruptions. They also found several theoretical applications in complexity theory, pseudorandomness, probabilistically checkable proofs and cryptography. Each application requires codes with specific properties. One such property desirable in many applications is ‘locality’. Locality refers to the ability to perform operations like decoding/correction/testing in sublinear or sometimes constant time. For example, a constant query locally decodable code (LDC) allows decoding of any message bit in constant time given a corrupted encoding of the message. Much of the work in this thesis is to understand the power and limitations of codes with locality. We show that one can get non-trivial locality and still match the best known rate-distance tradeoffs of traditional error correcting codes (Gilbert- Varshamov bound). We prove several conditional lower bounds on codes with locality and give new directions for constructing such codes by showing an analytic characterization of LDCs. We also explore applications of such codes to additive combinatorics, information privacy and data storage. We show how to use ideas from existing constructions of LDCs to design 2-server private information retrieval schemes where a user can efficiently and privately query a database replicated among two (non-communicating) servers without revealing any information about their query to either server. We also show limits and improved constructions of maximally recoverable local reconstruction codes which are locally correctable codes designed specifically for distributed data storage applications. Barbara A. Mooring Interim Graduate Coordinator Computer Science Department Princeton University

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Amy Tai PreFPO Wednesday, June 6, 2018 1:00 pm CS402
by Barbara A. Mooring 06 Jun '18

06 Jun '18

Amy Tai will present her PreFPO on Wednesday, June 6, 2018 at 1:00 pm in CS 402. Committee: Mike Freedman (advisor) Jen Rexford Kai Li Kyle Jamieson Wyatt Lloyd All are welcomed to attend. Title: Leveraging Distributed Storage Redundancy in Datacenters Abstract: Replication is a widely used primitive in distributed storage systems to achieve properties such as durability and availability. In this talk, I will discuss two projects in which we design and implement two novel properties that replication can achieve. With each property, we also define the set of tradeoffs introduced as well as propose new techniques for exploring these tradeoffs. Our work shows that replication has several more useful properties than previously assumed. First, I will discuss Replex, which harnesses distributed storage redundancy to build distributed secondary indices. Traditionally, storage systems punt on building fully functional distributed secondary indices because they do not have the correct primitive for doing so. We introduce a new replication primitive, a replex, that treats distributed secondary indices as first-class data objects. The tradeoff that results is between steady-state and failure performance, and we explore this tradeoff with a primitive we denote a hybrid replex. Second, I will discuss DIRECT, which is a set of principles for systematically leveraging storage redundancy to fix corruption errors in live production storage systems. Corruption errors are generally treated as device failures in today's storage systems, but we show that by fixing them online, we can extend the lifetime of flash devices by orders of magnitude. The tradeoff that results is between size of failure domain (and hence time to recovery) and ease of implementation. Barbara A. Mooring Interim Graduate Coordinator Computer Science Department Princeton University

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