| 1. |
- Hasselquist, David, et al.
(författare)
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Twitch Chat Fingerprinting
- 2022
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Ingår i: Proc. IFIP Network Traffic Measurement and Analysis Conference (TMA) 2022.
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Konferensbidrag (refereegranskat)abstract
- The streaming content that we choose to watch canreveal much about our thoughts, opinions, and interests. Anadversary capable of determining what users watch thereforepresents a significant privacy threat. In this paper, we presentand evaluate the first fingerprinting attack on Twitch that allowsviewers of individual live streams to be identified despite thetraffic being encrypted. The attack targets the traffic patternsassociated with chat messages associated with each stream. Ourresults show that high accuracy can be achieved by eavesdroppingonly for a short time (e.g., 90 seconds) and that the accuracy canbe increased even further by interacting with the stream. We alsotake a closer look at how the accuracy and activity level differbetween different Twitch channels and provide insights into theaccuracy that attackers using different strategies for selectingtarget channels may have. Finally, we study countermeasures toprotect against such attacks and demonstrate that the naive use ofVPN is not enough. We instead present countermeasures alteringpacket timing and sizes. Our large-scale evaluation of differentcountermeasures provides important insights that help both thestreaming providers and users better protect their privacy.
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| 2. |
- Aaro, Gustav, 1995-, et al.
(författare)
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Toolset for Run-time Dataset Collection of Deep-scene Information
- 2020
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Ingår i: Symposium on Modelling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS). - Cham : Springer. - 9783030681098 ; , s. 224-236
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Konferensbidrag (refereegranskat)abstract
- Virtual reality (VR) provides many exciting new application opportunities, but also present new challenges. In contrast to 360° videos that only allow a user to select its viewing direction, in fully immersive VR, users can also move around and interact with objects in the virtual world. To most effectively deliver such services it is therefore important to understand how users move around in relation to such objects. In this paper, we present a methodology and software tool for generating run-time datasets capturing a user’s interactions with such 3D environments, evaluate and compare different object identification methods that we implement within the tool, and use datasets collected with the tool to demonstrate example uses. The tool was developed in Unity, easily integrates with existing Unity applications through the use of periodic calls that extracts information about the environment using different ray-casting methods. The software tool and example datasets are made available with this paper.
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| 3. |
- Arvanitaki, Antonia, 1991-, et al.
(författare)
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Delay Performance of a Two-User Broadcast Channel with Security Constraints
- 2020
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Ingår i: SN Computer Science. - : Springer. - 2661-8907 .- 2662-995X. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider the two-user broadcast channel with security constraints. We assume that a source broadcasts packets to two receivers, and that one of them has secrecy constraints, i.e., its packets need to be kept secret from the other receiver. The receiver with secrecy constraint has full-duplex capability, allowing it to transmit a jamming signal to increase its secrecy. We derive the average delay per packet and provide simulations and numerical results, where we compare different performance metrics for the cases when both receivers treat interference as noise, when the legitimate receiver performs successive decoding, and when the eavesdropper performs successive decoding. The results show that successive decoding provides better average packet delay for the legitimate user. Furthermore, we define a new metric that characterizes the reduction on the success probability for the legitimate user that is caused by the secrecy constraint. The results show that secrecy poses a significant amount of packet delay for the legitimate receiver when either receiver performs successive decoding. We also formulate an optimization problem, wherein the throughput of the eavesdropper is maximized under delay and secrecy rate constraints at the legitimate receiver. We provide numerical results for the optimization problem, where we show the trade-off between the transmission power for the jamming and the throughput of the non-legitimate receiver. The results provide insights into how channel ordering and encoding differences can be exploited to improve performance under different interference conditions.
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| 4. |
- Arvanitaki, Antonia, 1991-, et al.
(författare)
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Secrecy in Congestion-Aware Broadcast Channels
- 2021
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Ingår i: Proc. Wireless Days Conference (WD) 2021. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665425599 - 9781665425605
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Konferensbidrag (refereegranskat)abstract
- Congestion-aware scheduling in the case of traditional downlink cellular communication has neglected the heterogeneity in terms of secrecy among different clients. In this paper, we study a two-user congestion-aware broadcast channel with heterogeneous traffic and different security requirements. The traffic with security requirements is intended for a legitimate user and it has bursty nature. The incoming packets are stored in a queue at the source. Furthermore, there is a second traffic flow intended for another user, it is delay tolerant and does not have secrecy constraints. The receiver which needs to be served with confidential data has full-duplex capabilities, and it can send a jamming signal to hinder eavesdropping of its data at the other user. We consider two randomized policies for selecting which packets to transmit, one is congestion-aware by taking into consideration the queue size, whereas the other one is non-congestion-aware. We analyse the throughput and the delay performance under two decoding schemes at the receivers and provide insights into their relative security performance and into how congestion control at the queue holding confidential information can help decrease the average delay per packet. We show that the two policies have the same secrecy performance for large random access probabilities. The derived results also take account of the self-interference caused at the receiver for whom confidential data is intended due to its full-duplex operation while jamming the communication at the other user.
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| 5. |
- Bertmar, Sofia, et al.
(författare)
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Who's Most Targeted and Does My New Adblocker Really Help : A Profile-based Evaluation of Personalized Advertising
- 2021
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Ingår i: Proc. ACM CCS Workshop on Privacy in the Electronic Society (ACM WPES @CCS). - New York, NY, USA : ACM Digital Library. - 9781450385275
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Konferensbidrag (refereegranskat)abstract
- There is limited prior work studying how the ad personalization experienced by different users is impacted by the use of adblockers, geographic location, the user's persona, or what browser they use. To address this void, this paper presents a novel profile-based evaluation of the personalization experienced by carefully crafted user profiles. Our evaluation framework impersonates different users and captures how the personalization changes over time, how it changes when adding or removing an extension, and perhaps most importantly how the results differ depending on the profile's persona (e.g., interest, occupation, age, gender), geographic location (US East, US West, UK), what browser extension they use (none, AdBlock, AdBlock Plus, Ghostery, CatBlock), what browser they use (Chrome, Firefox), and whether they are logged in to their Google account. By comparing and contrasting observed differences we provide insights that help explain why some user groups may feel more targeted than others and why some people may feel even more targeted after having turned on their adblocker.
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| 6. |
- Bruhner, Carl Magnus, 1988-, et al.
(författare)
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Bridging the Privacy Gap: Enhanced User Consent Mechanisms on the Web
- 2023
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Ingår i: Proc. NDSS Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb @NDSS). - Reston, VA : Internet Society. - 1891562878
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Konferensbidrag (refereegranskat)abstract
- In the age of the General Data Protection Regula-tion (GDPR) and the California Consumer Privacy Act (CCPA),privacy and consent control have become even more apparent forevery-day web users. Privacy banners in all shapes and sizes askfor permission through more or less challenging designs and makeprivacy control more of a struggle than they help users’ privacy.In this paper, we present a novel solution expanding the AdvancedData Protection Control (ADPC) mechanism to bridge currentgaps in user data and privacy control. Our solution moves theconsent control to the browser interface to give users a seamlessand hassle-free experience, while at the same time offering contentproviders a way to be legally compliant with legislation. Throughan extensive review, we evaluate previous works and identifycurrent gaps in user data control. We then present a blueprintfor future implementation and suggest features to support privacycontrol online for users globally. Given browser support, thesolution provides a tangible path to effectively achieve legallycompliant privacy and consent control in a user-oriented mannerthat could allow them to again browse the web seamlessly.
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| 7. |
- Carlsson, Niklas, 1977-, et al.
(författare)
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Cross-user Similarities in Viewing Behavior for 360°Video and Caching Implications
- 2023
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : ASSOC COMPUTING MACHINERY. - 1551-6857 .- 1551-6865. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- The demand and usage of 360°video services are expected to increase. However, despite these services being highly bandwidth intensive, not much is known about the potential value that basic bandwidth saving techniques such as server or edge-network on-demand caching (e.g., in a CDN) could have when used for delivery of such services. This problem is both important and complicated as client-side solutions have been developed that split the full 360°view into multiple tiles, and adapt the quality of the downloaded tiles based on the user’s expected viewing direction and bandwidth conditions. This paper presents new trace-based analysis methods that incorporate users’ viewports (the area of the full 360°view the user actually sees), a first characterization of the cross-user similarities of the users’ viewports, and a trace-based analysis of the potential bandwidth savings that caching-based techniques may offer under different conditions. Our analysis takes into account differences in the time granularity over which viewport overlaps can be beneficial for resource saving techniques, compares and contrasts differences between video categories, and accounts for uncertainties in the network conditions and the prediction of the future viewing direction when prefetching. The results provide substantial insight into the conditions under which overlap can be considerable and caching effective, and inform the design of new caching system policies tailored for 360°video.
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| 8. |
- Carlsson, Niklas, 1977-, et al.
(författare)
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Optimized Dynamic Cache Instantiation and Accurate LRU Approximations under Time-varying Request Volume
- 2023
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Ingår i: IEEE Transactions on Cloud Computing. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2168-7161 .- 2372-0018. ; 11:1, s. 779-797
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Tidskriftsartikel (refereegranskat)abstract
- Content-delivery applications can achieve scalability and reduce wide-area network traffic using geographically distributed caches. However, each deployed cache has an associated cost, and under time-varying request rates (e.g., a daily cycle) there may be long periods when the request rate from the local region is not high enough to justify this cost. Cloud computing offers a solution to problems of this kind, by supporting dynamic allocation and release of resources. In this paper, we analyze the potential benefits from dynamically instantiating caches using resources from cloud service providers. We develop novel analytic caching models that accommodate time-varying request rates, transient behavior as a cache fills following instantiation, and selective cache insertion policies. Within the context of a simple cost model, we then develop bounds and compare policies with optimized parameter selections to obtain insights into key cost/performance tradeoffs. We find that dynamic cache instantiation can provide substantial cost reductions, that potential reductions strongly dependent on the object popularity skew, and that selective cache insertion can be even more beneficial in this context than with conventional edge caches. Finally, our contributions also include accurate and easy-to-compute approximations that are shown applicable to LRU caches under time-varying workloads.
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| 9. |
- de Leng, Daniel, 1988-, et al.
(författare)
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Second Screen Journey to the Cup: Twitter Dynamics during the Stanley Cup Playoffs
- 2018
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Ingår i: Proceedings of the 2nd Network Traffic Measurement and Analysis Conference (TMA). - 9783903176096 - 9781538671528 ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- With Twitter and other microblogging services, users can easily express their opinion and ideas in short text messages. A recent trend is that users use the real-time property of these services to share their opinions and thoughts as events unfold on TV or in the real world. In the context of TV broadcasts, Twitter (over a mobile device, for example) is referred to as a second screen. This paper presents the first characterization of the second screen usage over the playoffs of a major sports league. We present both temporal and spatial analysis of the Twitter usage during the end of the National Hockey League (NHL) regular season and the 2015 Stanley Cup playoffs. Our analysis provides insights into the usage patterns over the full 72-day period and with regards to in-game events such as goals, but also with regards to geographic biases. Quantifying these biases and the significance of specific events, we then discuss and provide insights into how the playoff dynamics may impact advertisers and third-party developers that try to provide increased personalization.
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| 10. |
- González Dos Santos, Teno, et al.
(författare)
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Predicting Season Outcomes for the NBA
- 2022
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Ingår i: Machine Learning and Data Mining for Sports Analytics. - Cham, Switzerland : Springer. - 9783031020438 - 9783031020445 ; , s. 129-142
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Konferensbidrag (refereegranskat)abstract
- Predicting game or season outcomes is important for clubs as well as for the betting industry. Understanding the critical factors of winning games and championships gives clubs a competitive advantage when selecting players for the team and implementing winning strategies. In this paper, we work with NBA data from 10 seasons and propose an approach for predicting game outcomes that is then used for predicting which team will be champion and which stages a team will reach in the playoffs. We show that our approach has a similar performance as the odds from betting companies and does better than ELO.
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