Abbas Razaghpanah

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Mobile phones now offer users capabilities that rival those of general purpose computers. However, despite the myriad applications they support, mobile systems remain notoriously opaque. Mobile operating systems tightly control access to system resources and network traffic. The opacity of mobile systems to monitoring presents two serious drawbacks. First,(More)
Traffic differentiation---giving better (or worse) performance to certain classes of Internet traffic---is a well-known but poorly understood traffic management policy. There is active discussion on whether and how ISPs should be allowed to differentiate Internet traffic, but little data about current practices to inform this discussion. Previous work(More)
Understanding network reliability and outages is critical to the “health” of the Internet infrastructure. Unfortunately, our ability to analyze Internet outages has been hampered by the lack of access to public information from key players. In this paper, we leverage a somewhat unconventional dataset to analyze Internet reliability—the outages mailing list.(More)
Despite the high perceived value and increasing severity of online information controls, a data-driven understanding of the phenomenon has remained elusive. In this paper, we consider two design points in the space of Internet censorship measurement with particular emphasis on how they address the challenges of locating vantage points, choosing content to(More)
Despite our growing reliance on mobile phones for a wide range of daily tasks, their operation remains largely opaque. A number of previous stud­ ies have addressed elements of this problem in a par­ tial fashion, trading off analytic comprehensiveness and deployment scale. We overcome the barriers to largescale deployment (e.g., requiring rooted devices)(More)
The goal of this research is to detect traffic differentiation in cellular data networks. We define service differentiation as any attempt to change the performance of network traffic traversing an ISP's boundaries. ISPs may implement differentiation policies for a number of reasons, including load balancing, bandwidth management, or business reasons.(More)
Third-party services form an integral part of the mobile ecosystem: they allow app developers to add features such as performance analytics and social network integration, and to monetize their apps by enabling user tracking and targeted ad delivery. At present users, researchers, and regulators all have at best limited understanding of this third-party(More)
In recent years, a market of games and learning apps for children has flourished in the mobile world. Many of these often “free” mobile apps have access to a variety of sensi­ tive personal information about the user, which the app au­ thor can leverage to increase revenue via advertising or other means. In the United States, the Children’s Online Privacy(More)
Recent years have seen the Internet become a key vehicle for citizens around the globe to express political opinions and organize protests. This fact has not gone unnoticed, with countries around the world repurposing network management tools (e.g., URL ltering products) and protocols (e.g., BGP, DNS) for censorship. However, repurposing these products can(More)