Florian Tschorsch

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Besides attracting a billion dollar economy, Bitcoin revolutionized the field of digital currencies and influenced many adjacent areas. This also induced significant scientific interest. In this survey, we unroll and structure the manyfold results and research directions. We start by introducing the Bitcoin protocol and its building blocks. From there we(More)
Tor is a distributed onion-routing network used for achieving anonymity and resisting censorship online. Because of Tor’s growing popularity, it is attracting increasingly larger threats against which it was not securely designed. In this paper, we present the Sniper Attack, an extremely low cost but highly destructive denial of service attack against Tor(More)
Internet anonymity systems, like for instance Tor, are in widespread use today. Technically they are realized as overlays, i. e., they add another instance of routing, forwarding, and transport functionality on top of the Internet protocol stack. This has important (and often subtle) implications, as overlay and underlay may interact. Far too often,(More)
Many overlay-based distributed applications employ TCP for the communication between peer nodes. Typically, the TCP connections of one peer will all share one physical Internet link. Using real-world network experiments, we demonstrate that this can lead to undesirable interactions between overlay links, resulting in oscillations and suboptimal throughput.(More)
Tor has become the prime example for anonymous communication systems. With increasing popularity, though, Tor is also faced with increasing load. In this paper, we tackle one of the fundamental problems in today’s anonymity networks: network congestion. We show that the current Tor design is not able to adjust the load appropriately, and we argue that(More)
While location management is a key component of cellular networks, it is also a major privacy issue: location management empowers the network operator to track users. In today's public and scientific discussion, the centralized storage of location data is mostly taken as a fact, and users are expected to trust the network operator. With ANOTEL we present a(More)
In TCP-based overlay applications, the TCP connections of one peer typically share one physical Internet link. Using real-world experiments, we demonstrate that this can lead to undesirable interactions, causing significant throughput loss. We argue that such effects should be taken into account in the design of overlay networks, and identify readily(More)