Security, Privacy and Abuse Prevention

A streaming algorithm is said to be adversarially robust if its accuracy guarantees are maintained even when the data stream is chosen maliciously, by an adaptive adversary. We establish a connection between adversarial robustness of streaming algorithms and the notion of differential privacy. This connection allows us to design new adversarially robust streaming algorithms that outperform the...

Sharing multimedia content, without obtaining consent from the people involved causes multiparty privacy conflicts (MPCs). However, social-media platforms do not proactively protect users from the occurrence of MPCs. Hence, users resort to out-of-band, informal communication channels, attempting to mitigate such conflicts. So far, previous works have focused on hard interventions that do not...

“Exposure Notification (EN) Systems” which have been envisioned by a number of academic and industry groups, are useful in aiding health authorities worldwide to fight the COVID-19 pandemic spread via contact tracing. Among these systems, many rely on the BLE based Google-Apple Exposure Notification (GAEN) API (for iPhones and Android systems). We assert that it is now the time to investigate...

We present efficient differentially private algorithms for learning unions of polygons in the plane (which are not necessarily convex). Our algorithms are $(\alpha,\beta)$--probably approximately correct and $(\varepsilon,\delta)$--differentially private using a sample of size $\tilde{O}\left(\frac{1}{\alpha\varepsilon}k\log d\right)$, where the domain is $[d]\times[d]$ and $k$ is the number of...