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  • 1001.
    Vliegen, Jo
    et al.
    ESAT, SCD/COSIC, Katholieke Universiteit Leuven, 3001 Leuven, Belgium.
    Wouters, Karel
    ESAT, SCD/COSIC, Katholieke Universiteit Leuven, 3001 Leuven, Belgium.
    Grahn, Christian
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Pulls, Tobias
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Hardware strengthening a Distributed Logging Scheme2012In: In Proceedings ofthe 15th Euromicro Conference on Digital System Design, Cesme, Izmir,Turkey, September 5–8, IEEE, 2012, 2012Conference paper (Refereed)
  • 1002. Volkamer, Melanie
    et al.
    Renaud, Karen
    Braun, Kristoffer
    Canova, Gamze
    Reinheimer, Benjamin
    Design and Field Evaluation of PassSec Raising and Sustaining Web Surfer Risk Awareness2015In: Trust and Trustworthy Computing, 2015, p. 104-121Conference paper (Refereed)
    Abstract [en]

    This paper presents PassSec, a Firefox Add-on that raises user awareness about safe and unsafe password entry while they surf the web. PassSec comprises a two-stage approach: highlighting as the web page loads, then bringing up a just-in-time helpful dialog when the user demonstrates an intention to enter a password on an unsafe web page. PassSec was developed using a human-centered design approach. We performed a field study with 31 participants that showed that PassSec significantly reduces the number of logins on websites where password entry is unsafe.

  • 1003.
    Volkamer, Melanie
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science. Tech Univ Darmstadt, Darmstadt, Germany.
    Renaud, Karen
    University Glasgow, Scotland.
    Canova, Gamze
    Technical University Darmstadt, Germany.
    Reinheimer, Benjamin
    Technical University Darmstadt, Germany.
    Braun, Kristoffer
    Technical University Darmstadt, Germany.
    Design and Field Evaluation of PassSec: Raising and Sustaining Web Surfer Risk Awareness2015In: TRUST AND TRUSTWORTHY COMPUTING, TRUST 2015 / [ed] Conti, M Schunter, M Askoxylakis, I, Springer Berlin/Heidelberg, 2015, p. 104-122Conference paper (Refereed)
    Abstract [en]

    This paper presents PassSec, a Firefox Add-on that raises user awareness about safe and unsafe password entry while they surf the web. PassSec comprises a two-stage approach: highlighting as the web page loads, then bringing up a just-in-time helpful dialogue when the user demonstrates an intention to enter a password on an unsafe web page. PassSec was developed using a human-centred design approach. We performed a field study with 31 participants that showed that PassSec significantly reduces the number of logins on websites where password entry is unsafe.

  • 1004.
    Volkamer, Melanie
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Renaud, Karen
    Kulyk, Oksana
    Emeröz, Sinem
    An Investigation into the "Other" Barriers to Adoption of Smartphone Security Precautions (Poor Usability being a Given)2015Report (Other academic)
  • 1005.
    Volkamer, Melanie
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Renaud, Karen
    Reinheimer, Benjamin
    TORPEDO: TOoltip-poweRed Phishing Email DetectiOn2016In: ICT Systems Security and Privacy Protection: 31st IFIP TC 11 International Conference, SEC 2016, Ghent, Belgium, May 30 - June 1, 2016, Proceedings, Springer Berlin/Heidelberg, 2016, Vol. 471, p. 161-175Conference paper (Refereed)
  • 1006.
    Volkamer, Melanie
    et al.
    Tech Univ Darmstadt, CASED, SecUSO, Dept Comp Sci, Darmstadt, Germany..
    Stockhardt, Simon
    Tech Univ Darmstadt, CASED, SecUSO, Dept Comp Sci, Darmstadt, Germany..
    Bartsch, Steffen
    Tech Univ Darmstadt, CASED, SecUSO, Dept Comp Sci, Darmstadt, Germany..
    Kauer, Michaela
    Tech Univ Darmstadt, CASED, SecUSO, Dept Comp Sci, Darmstadt, Germany..
    Adopting the CMU/APWG anti-phishing landing page idea for Germany2013In: 2013 THIRD WORKSHOP ON SOCIO-TECHNICAL ASPECTS IN SECURITY AND TRUST (STAST 2013), IEEE Press, 2013, p. 46-52Conference paper (Refereed)
    Abstract [en]

    Phishing attacks still pose a significant problem and purely technical solutions cannot solve this problem. While research literature in general shows that educating users in security is hard, the Anti-Phishing Landing Page proposed by CMU researchers seems promising as it appears in the most teachable moment - namely once someone clicked on a link and was very likely to fall for phishing. While this page is already in use and exists in many languages we show that it is not effective in Germany as most users leave the page immediately without having read any advice. We therefore explore options to adopt their ideas for Germany. We focus on which are the trustworthy institutes that could provide such a landing page on their web pages and what is an appropriate headline and design.

  • 1007.
    Voronkov, Artem
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Systematic Literature Review on Usability of Firewall Configuration2018In: ACM Computing Surveys, ISSN 0360-0300, E-ISSN 1557-7341, Vol. 50, no 6, article id 87Article in journal (Other academic)
    Abstract [en]

    Firewalls are network security components that handle incoming and outgoing network traffic based on a set of rules. The process of correctly configuring a firewall is complicated and prone to error, and it worsens as the network complexity grows. A poorly configured firewall may result in major security threats; in the case of a network firewall, an organization’s security could be endangered, and in the case of a personal firewall, an individual computer’s security is threatened. A major reason for poorly configured firewalls, as pointed out in the literature, is usability issues. Our aim is to identify existing solutions that help professional and non-professional users to create and manage firewall configuration files, and to analyze the proposals in respect of usability. A systematic literature review with a focus on the usability of firewall configuration is presented in the article. Its main goal is to explore what has already been done in this field. In the primary selection procedure, 1,202 articles were retrieved and then screened. The secondary selection led us to 35 articles carefully chosen for further investigation, of which 14 articles were selected and summarized. As main contributions, we propose a taxonomy of existing solutions as well as a synthesis and in-depth discussion about the state of the art in firewall usability. Among the main findings, we perceived that there is a lack (or even an absence) of usability evaluation or user studies to validate the proposed models. Although all articles are related to the topic of usability, none of them clearly defines it, and only a few actually employ usability design principles and/or guidelines.

  • 1008.
    Voronkov, Artem
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Usable Firewall Rule Sets2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Correct functioning is the most important requirement for any system. Nowadays there are a lot of threats to computer systems that undermine confidence in them and, as a result, force a user to abandon their use. Hence, a system cannot be trusted if there is no proper security provided. Firewalls are an essential component of network security and there is an obvious need for their use.

    The level of security provided by a firewall depends on how well it is configured. Thus, to ensure the proper level of network security, it is necessary to have properly configured firewalls. However, setting up the firewall correctly is a very challenging task. These configuration files might be hard to understand even for system administrators. This is due to the fact that these configuration files have a certain structure: the higher the position of a rule in the rule set, the higher priority it has. Challenging problems arise when a new rule is being added to the set, and a proper position, where to place it, needs to be found. Misconfiguration might sooner or later be made and that will lead to an inappropriate system's security. This brings us to the usability problem associated with the configuration of firewalls.

    The overall aim of this thesis is to identify existing firewall usability gaps and to mitigate them. To achieve the first part of the objective, we conducted a series of interviews with system administrators. In the interviews, system administrators were asked about the problems they face when dealing with firewalls. After having ascertained that the usability problems exist, we turned to literature to get an understanding on the state-of-the-art of the field and therefore conducted a systematic literature review. This review presents a classification of available solutions and identifies open challenges in this area. To achieve the second part of the objective, we started working on one identified challenge. A set of usability metrics was proposed and mathematically formalized. A strong correlation between our metrics and how system administrators describe usability was identified.

  • 1009.
    Voronkov, Artem
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Iwaya, Leonardo H
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Systematic Literature Review on Usability of Firewall Configuration2018In: ACM Computing Surveys, ISSN 0360-0300, E-ISSN 1557-7341, Vol. 50, no 6, article id 87Article in journal (Refereed)
    Abstract [en]

    Firewalls are network security components that handle incoming and outgoing network traffic based on a set of rules. The process of correctly configuring a firewall is complicated and prone to error, and it worsens as the network complexity grows. A poorly configured firewall may result in major security threats; in the case of a network firewall, an organization’s security could be endangered, and in the case of a personal firewall, an individual computer’s security is threatened. A major reason for poorly configured firewalls, as pointed out in the literature, is usability issues. Our aim is to identify existing solutions that help professional and non-professional users to create and manage firewall configuration files, and to analyze the proposals in respect of usability. A systematic literature review with a focus on the usability of firewall configuration is presented in the article. Its main goal is to explore what has already been done in this field. In the primary selection procedure, 1,202 articles were retrieved and then screened. The secondary selection led us to 35 articles carefully chosen for further investigation, of which 14 articles were selected and summarized. As main contributions, we propose a taxonomy of existing solutions as well as a synthesis and in-depth discussion about the state of the art in firewall usability. Among the main findings, we perceived that there is a lack (or even an absence) of usability evaluation or user studies to validate the proposed models. Although all articles are related to the topic of usability, none of them clearly defines it, and only a few actually employ usability design principles and/or guidelines.

  • 1010.
    Vromans, Arthur
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Tech Univ Eindhoven, Ctr Anal Sci Comp & Applicat CASA, Den Dolech 2, NL-5612 AZ Eindhoven, Netherlands.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    van de Ven, Fons
    Tech Univ Eindhoven, Ctr Anal Sci Comp & Applicat CASA, AZ Eindhoven, Netherlands.
    A mixture theory-based concrete corrosion model coupling chemical reactions, diffusion and mechanics2018In: PACIFIC JOURNAL OF MATHEMATICS FOR INDUSTRY, ISSN 2198-4115, Vol. 10, article id 5Article in journal (Refereed)
    Abstract [en]

    A 3-D continuum mixture model describing the corrosion of concrete with sulfuric acid is built. Essentially, the chemical reaction transforms slaked lime (calcium hydroxide) and sulfuric acid into gypsum releasing water. The model incorporates the evolution of chemical reaction, diffusion of species within the porous material and mechanical deformations. This model is applied to a 1-D problem of a plate-layer between concrete and sewer air. The influx of slaked lime from the concrete and sulfuric acid from the sewer air sustains a gypsum creating chemical reaction (sulfatation or sulfate attack). The combination of the influx of matter and the chemical reaction causes a net growth in the thickness of the gypsum layer on top of the concrete base. The model allows for the determination of the plate layer thickness h = h(t) as function of time, which indicates both the amount of gypsum being created due to concrete corrosion and the amount of slaked lime and sulfuric acid in the material. The existence of a parameter regime for which the model yields a non-decreasing plate layer thickness h(t) is identified numerically. The robustness of the model with respect to changes in the model parameters is also investigated.

  • 1011.
    Vähäsalo, Mattias
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Prediktiv modellering: Processen att skapa prediktiva modeller med Azure Machine Learning2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 1012.
    Västlund, Filip
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Video Flow Classification: A Runtime Performance Study2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to it being increasingly common that users' data is encrypted, the Internet service providers today find it difficult to adapt their service for the users' needs. Previously popular methods of classifying users data does not work as well today and new alternatives is therefore desired to give the users an optimal experience.This study focuses specifically on classifying data flows into video and non-video flows with the use of machine learning algorithms and with a focus on runtime performance. In this study the tested algorithms are created in Python and then exported into a C code implementation, more specifically the random forest and the gradient boosting trees algorithm.The goal is to find the algorithm with the fastest classification time relative to its accuracy, making the classification as fast as possible and the classification model to require as little space as possible.The results show that random forest was significantly faster at classification than gradient boosting trees, with initial tests showing it to be roughly 7 times faster after compiler optimization. After optimizing the C code random forest could classify more than 250,000 data flows each second with decent accuracy. Neither of the two algorithms required a lot of space (<3 megabyte).

  • 1013.
    Wahlqvist, Alexander
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Portning av applikationen Vasasvahn2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today's society it is important to easily and smoothly get accurate information. Withthe help of the application VasaSvahn it is possible to get expert help for Crosscountry ski waxing. The application VasaSvahn has been ported from an existingversion for iOS to a new version for Android. The application uses a third-party Webservices to obtain necessary information and support distribution of information. Theapplication is also connected to a database. The information the user needs to getaccurate waxing tips is stored in this database.The user of the application can also save information about the waxing selected atany given time and its external conditions. This report describes in detail how theapplication is built and the design decisions made when porting the application. Inthis report can also an evaluation of the application development tool Xamarin befound.

  • 1014. Wang, Tai-Chun
    et al.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Averaging Measurement Strategies for Identifying Single Nucleotide Polymorphisms from Redundant Data Sets2011In: IEEE/ACS International Conference on Computer Systems and Applications (AICCSA-2011), Sharm El-Sheikh: IEEE Press, 2011, p. 67-74Conference paper (Refereed)
  • 1015.
    Wang, Tai-Chun
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    RadixHap: a radix tree-based heuristic for solving the single individual haplotyping problem2015In: International Journal of Bioinformatics Research and Applications, ISSN 1744-5485, E-ISSN 1744-5493, Vol. 11, no 1, p. 10-29Article in journal (Refereed)
  • 1016.
    Wang, Tai-Chun
    et al.
    Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Using genetic algorithm in reconstructing single individual haplotype with minimum error correction2012In: Journal of Biomedical Informatics, ISSN 1532-0464, E-ISSN 1532-0480, Vol. 45, no 5, p. 922-930Article in journal (Refereed)
    Abstract [en]

    Discovering ways to reconstruct reliable Single Individual Haplotypes (SIHs) becomes one of the core issues in the whole-genome research nowadays as previous research showed that haplotypes contain more information than individual Singular Nucleotide Polymorphisms (SNPs). Although with advances in high-throughput sequencing technologies obtaining sequence information is becoming easier in today's laboratories, obtained sequences from current technologies always contain inevitable sequence errors and missing information. The SIH reconstruction problem can be formulated as bi-partitioning the input SNP fragment matrix into paternal and maternal sections to achieve minimum error correction (MEC) time; the problem that is proved to be NP-hard. Several heuristics or greedy algorithms have already been designed and implemented to solve this problem, most of them however (1) do not have the ability to handle data sets with high error rates and/or (2) can only handle binary input matrices. In this study, we introduce a Genetic Algorithm (GA) based method, named GAHap, to reconstruct SIHs with lowest MEC times. GAHap is equipped with a well-designed fitness function to obtain better reconstruction rates. GAHap is also compared with existing methods to show its ability in generating highly reliable solutions.

  • 1017. Weber, Stefan G.
    et al.
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ries, Sebastian
    Mühlhäuser, Max
    Technische Universität Darmstadt.
    Towards trustworthy identity and access management for the future internet2010In: Proceedings of the 4th International Workshop on Trustworthy Internet ofPeople, Things & Services (Trustworthy IoPTS 2010), 2010Conference paper (Refereed)
    Abstract [en]

    The Future Internet, in its different variants, promises a global connectivity of people, things and services.However, in order to develop its full potential and to achieve an accepted, seamless integration of Internet use into daily lives, severe security issues have to be addressed. In this paper, we propose to establish security and trustworthiness by means of an integrated identity and access management. Especially, we sketch the foundations of a novel identity and access management approach that is tailored for the Future Internet. We provide mechanisms for flexible modeling and description of digital user identities with support to transaction-based privacy protection, access to personal data, flexible third party accountability and end-to-end secure communication. The mechanisms are tailored for the use on a trusted personaldevice called Minimal Entity, which provides a trustworthy gateway to benefit from the offerings of the Future Internet.

  • 1018.
    Wennström (Klockar), Annika
    Karlstad University, Division for Information Technology.
    A Measurement Based Performance Study of TCP over GSM/GPRS2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, the performance of the wireless Internet is studied with a focus on TCP over GSM/GPRS. To this end, we have developed a GSM/GPRS test bed for TCP measurements. We present measurements conducted in the test bed with TCP over both GSM and GPRS. The GSM measurements show that TCP interacts efficiently with the radio link layer in GSM, also under very poor radio conditions. The only cases when some inefficiency is detected occur due to sudden variations in delay. In GPRS, delay is, among other things, caused by buffering in intermediate nodes and by dynamic resource sharing. The GPRS measurements indicate that if the buffers in intermediate nodes are reduced, then the delay can be decreased significantly with almost retained throughput. Dynamic resource sharing is often configured to give preemptive priority to voice calls, which implies that all GPRS resources may be lost. Measurements with preemptive priority indicate that TCP performance is degraded more than necessary due to inefficient buffer management. The situation would improve if data was buffered during preemption and if the data was transmitted immediately as GPRS resources become available again

  • 1019.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    TCP over GPRS: The Effect of Preemption2003Conference paper (Refereed)
    Abstract [en]

    GPRS extends the widely deployed GSM system with a more efficient wireless Internet access. In this paper we present measurements of GPRS traffic when preempted by circuit-switched calls. The results indicate that TCP performance is degraded more than necessary, as buffered data is flushed immediately when the GPRS traffic is preempted. The time required for error recovery is considerable also for very short preemtion periods.

  • 1020.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    Rendón, Juan
    Impact of GPRS buffering on TCP performance2004In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, IEE Electronics Letters Volume 40, Issue 20, 30 Sept. 2004 Page(s): 1279-1281, Vol. 40, no 20, p. 1279-1281Article in journal (Refereed)
    Abstract [en]

    GPRS networks, excessive buffering has a negative effect on TCP as the round trip times become very long. Measurements with different buffer settings indicate that the queueing delay can be reduced by orders of magnitude with a smaller buffer, without significantly degrading TCP throughput. The measurements are conducted in a GPRS testbed consisting of real network nodes.

  • 1021.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    Rendón, Juan
    Technology Dept., Pompeu Fabra University, Barcelona, Spain.
    Gustafsson, J. H.
    Telia Mobile AB, Karlstad, Sweden.
    The Impact of Preemptive Priority in GPRS on TCP Performance: A Measurement Study2004In: The first International Workshop on TCP and MAC Protocols in Wireless and Wired Networks, 2004, p. 430-436Conference paper (Refereed)
    Abstract [en]

    GPRS extends the widely deployed GSM system with a more effecient wireless Internet access. In this paper we investigate how a TCP transmission over GPRS is affected when it loses all its resources due to preemption by circuit-switched calls with higher priority. The results indicate that TCP performance is degraded more than necessary, as buffered data is flushed immediately when the GPRS traffic is preempted. The time required for error recovery is considerable also for very short preemption periods. The situation would improve if data was buffered during preemption and if the data was transmitted immediately as GPRS resources become available again.

  • 1022.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    Rendón, Juan
    Technology Dept., Pompeu Fabra University, Barcelona, Spain.
    Gustafsson, Jan H.
    Telia Mobile, Karlstad, Sweden.
    A GPRS Testbed for TCP Performance Measurements2002In: 4th International Workshop on Mobile and Wireless Communications Network, IEEE conference proceedings, 2002, p. 320-324Conference paper (Refereed)
    Abstract [en]

    In this paper a GPRS measurement testbed for TCP performance evaluation is presented. Unlike simulations and live measurements, the testbed combines the use of real network equipment and protocol implementations with a precise control over radio channel conditions. Some initial TCP measurements obtained with the GPRS testbed are also presented. The effect of varying numbers of PDCH and of buffering in the GPRS system is investigated.

  • 1023.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    Rendón, Juan
    Gustafsson, Jan H.
    The Impact of GPRS Buffering on TCP Performance2003Report (Refereed)
    Abstract [en]

    Wireless Internet access over GPRS, the packet-oriented extension to GSM, provides for higher data rates and more efficient network utilization compared to circuit-switched access. The performance of the Internet protocols in GPRS is dependent not only on the quality of the radio link, but also on the buffering in the GPRS network. In this paper we investigate the impact of buffering on TCP performance. Measurements are conducted in a GPRS testbed consisting of real network nodes with real protocol implementations. When the buffer between the fixed and the wireless networks is large, then the round trip times may become very long. Measurements with different buffer settings indicate that the buffer could be decreased in order to reduce the queuing delay, without degrading the throughput. Measurements of concurrent packet- and circuit-switched traffic show that buffered data is flushed immediately as the GPRS traffic is preempted by circuit-switched calls. When resources are available again, the lost data must be retransmitted. In many cases this could be avoided by guarding the data with a timer

  • 1024.
    Wennström (Klockar), Annika
    et al.
    Karlstad University, Division for Information Technology.
    Garcia, Johan
    Karlstad University, Division for Information Technology.
    Brunström, Anna
    Karlstad University, Division for Information Technology.
    Gustafsson, Jan H.
    Telia Mobile AB, Karlstad, Sweden.
    TCP and GSM Link Layer Interactions: Implications for the Wireless Internet2001In: IEEE VTS 53rd Vehicular Technology Conference, 2001, IEEE conference proceedings, 2001, p. 2198-2202Conference paper (Refereed)
    Abstract [en]

    The demand for wireless access to the Internet has grown rapidly making the performance of TCP in wireless environments an important issue. We present experimental measurements of the performance of TCP over GSM. The measurements were captured over a real GSM network connected to a controlled radio environment. A range of radio conditions were considered with a focus on the interaction between TCP and the GSM link layer. Even for very poor radio conditions, only neglible negative interaction effects were found.

  • 1025.
    Westlinder, Simon
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Video Traffic Classification: A Machine Learning approach with Packet Based Features using Support Vector Machine2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Internet traffic classification is an important field which several stakeholders are dependent on for a number of different reasons. Internet Service Providers (ISPs) and network operators benefit from knowing what type of traffic that propagates over their network in order to correctly treat different applications. Today Deep Packet Inspection (DPI) and port based classification are two of the more commonly used methods in order to classify Internet traffic. However, both of these techniques fail when the traffic is encrypted. This study explores a third method, classifying Internet traffic by machine learning in which the classification is realized by looking at Internet traffic flow characteristics instead of actual payloads. Machine learning can solve the inherent limitations that DPI and port based classification suffers from. In this study the Internet traffic is divided into two classes of interest: Video and Other. There exist several machine learning methods for classification, and this study focuses on Support Vector Machine (SVM) to classify traffic. Several traffic characteristics are extracted, such as individual payload sizes and the longest consecutive run of payload packets in the downward direction. Several experiments using different approaches are conducted and the achieved results show that overall accuracies above 90% are achievable.

  • 1026.
    Winberg, André
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Golrang, Ramin Alberto
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Analytics as a Service: Analysis of services in Microsoft Azure2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 1027. Wolf, Peter
    et al.
    Barrat, Jordi
    Bolo, Eden
    Bravo, Alejandro
    Krimmer, Robert
    Neumann, Stephan
    Parreño, Al A.
    Schürmann, Carsten
    Volkamer, Melanie
    Certification of ICTs in Elections2015Book (Other academic)
  • 1028.
    Wu, Hao
    et al.
    The University of Sydney, Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    B-Alarm: An Entropy Based Burst Traffic Prediction Approach for Ethernet Switches in Data Centers2013In: High Performance Computing and Communications & 2013 IEEE International Conference on Embedded and Ubiquitous Computing (HPCC_EUC), 2013 IEEE 10th International Conference on, IEEE conference proceedings, 2013Conference paper (Refereed)
  • 1029.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Angulo, Julio
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Evoking Comprehensive Mental Models of Anonymous Credentials2012In: Proceedings of the 2011 IFIP WG 11.4 international conference on Open Problems in Network Security / [ed] Camenisch J., Kesdogan, D., Berlin: Springer Berlin/Heidelberg, 2012, Vol. 7039, p. 1-14Conference paper (Refereed)
    Abstract [en]

    Anonymous credentials are a fundamental technology for preserving end users' privacy by enforcing data minimization for online applications. However, the design of user-friendly interfaces that convey their privacy benefits to users is still a major challenge. Users are still unfamiliar with the new and rather complex concept of anonymous credentials, since no obvious real-world analogies exists that can help them create the correct mental models. In this paper we explore different ways in which suitable mental models of the data minimization property of anonymous credentials can be evoked on end users. To achieve this, we investigate three different approaches in the context of an e-shopping scenario: a card-based approach, an attribute-based approach and an adapted card-based approach. Results show that the adapted card-based approach is a good approach towards evoking the right mental models for anonymous credential applications. However, better design paradigms are still needed to make users understand that attributes can be used to satisfy conditions without revealing the value of the attributes themselves.

  • 1030.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Graf, Conny
    Hochleitner, Christina
    Wolkerstorfer, Peter
    Angulo, Julio
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Final HCI Research Report: Deliverable D4.1.52011Report (Refereed)
    Abstract [en]

    This deliverable provides an overview of recent research results of Activity 4 ‘Usability’ of PrimeLife, where an emphasis is put on those results, which have not been reported in the same detail in other HCI-related PrimeLife deliverables yet. The first part reports about our results in the area of User Interface (UI) Representation of Privacyenhancing Identity Management Concepts and presents research on PET methodologies, mental models for anonymous credentials and the results from the final round of end-user evaluations of the UI prototypes developed during the PrimeLife project. The second part reports about our work in the area of usable privacy policies and presents the final results of Activity 4’s research on policy icons and on a user-friendly management and display of PPL (PrimeLife Policy Language) policies.

  • 1031.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Graf, Cornelia
    Hochleitner, Christina
    Wolkerstorfer, Peter
    Angulo, Julio
    Towards Usable Privacy Enhancing Technologies: Lessons Learned from the PrimeLife Project2011Report (Other academic)
    Abstract [en]

    In this deliverable, we present lessons learnt from the PrimeLife HCI (Human Computer Interaction) Activity by discussing typical HCI challenges and fallacies that we experienced during the PrimeLife project. We also provide guidance on how these issues can be addressed in order to develop usable privacy-enhancing technology solutions.

  • 1032.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer Hübner, SimoneKarlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.Köffel, CWolkerstorfer, Peter
    HCI Research Report: Version 12009Collection (editor) (Other academic)
    Abstract [en]

    One of the core activities in the PrimeLife  project is the design and implementation of privacy aware applications that are usable. Therefore it is the main objective of Activity 4 to assure the usability of those applications and advance the research in this area. The First HCI Research Report presents the main research results of the HCI activity within the first year of PrimeLife. The HCI Research Report V1 presents work in progress and will be updated and complemented by a second version, the Final HCI Research Report (D4.1.5), which will be published at the end of the PrimeLife project.

  • 1033.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Wolkerstorfer, Peter
    Usability Challenges of Privacy Technologies2011Conference paper (Other (popular science, discussion, etc.))
  • 1034.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Zwingelberg, Harald
    UI prototypes: Policy administration and presentation (version 1)2009Report (Refereed)
    Abstract [en]

    Privacy Policies are an important prerequisite for user control in privacy-enhancing identity management. The transparency of privacy policies can be enhanced if users are informed about mismatches of a site’s policy with the user’s preferences. Investigating understandable and transparent privacy policies as well as simplified and usable privacy preference (data release policy) management "on the fly" are the objectives of the deliverable. For this, it is discussing icons presenting the content of policies and different User Interface (UI) prototypes for policy display and preference administration, which have been partly compared and tested in an Online user study. Finally, legal requirements for policy display in social network sites and how they translate to Human Computer Interaction (HCI) requirements are investigated.

  • 1035.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    End User Transparency Tools: UI Prototypes2010Report (Refereed)
    Abstract [en]

    The Data Track is a user-side transparency-enhancing tool developed in PrimeLife, which provides the users with a history function documenting what personal data the user has revealed to whom under which conditions. Besides, it provides online functions to access the user’s personal data at the remote services side. This deliverable documents PrimeLife work package 4.2’s work on a usable Data Track. After introducing into the Data Track functionalities and the technical background, we will present the results of five iterations of user interface developments and usability testing, which we performed at Karlstad University and at CURE. We also present our initial work on a Data Track for social communities as well as on a Data Track for lifelong privacy.

  • 1036.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    The Users' Mental Models' Effect on their Comprehension of Anonymous Credentials2011In: Privacy and Identity Management for Life / [ed] Camenisch, J.; Fischer-Hübner, S.; Rannenberg, K., Heidelberg: Springer , 2011, p. 233-244Chapter in book (Other academic)
    Abstract [en]

    Anonymous Credentials are a key technology for enforcing data minimisation for online applications. The design of easily understandable user interfaces for the use of anonymous credentials is however a major challenge, as end users are not yet familiar with this rather new and complex technology and no obvious real-world analogies exist for them. In this chapter, we analyse what effects the users’ mental models have on their understanding of the data minimization property of anonymous credentials in the context of an e-Shopping application scenario. In particular, we have investigated the effects of the mental models of a card-based user interface approach and an attribute-based user interface approach and compared these in terms of errors of omission and addition. The results show that the card-based approach leads to significantly more errors of addition (i.e., users believe that they have disclosed more information than they actually have) whereas the attribute-based approach leads to more errors of omission (i.e., users underestimate the amount of data that they have disclosed).

  • 1037.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Wolkerstorfer, Peter
    Austria.
    PET-USES2011In: Privacy and Identity Management for Life / [ed] Camenisch, Fischer-Hübner, Rannenberg, Heidelberg: Springer Berlin/Heidelberg, 2011Chapter in book (Other academic)
  • 1038.
    Yang, Ting
    et al.
    China, Australia.
    Sun, Yugeng
    China.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    DLS: A Dynamic Local Stitching Mechanism to Rectify Transmitting Path Fragments in Wireless Sensor Networks2013In: Journal of Network and Computer Applications, ISSN 1084-8045, E-ISSN 1095-8592, Vol. 16, no 1, p. 306-315Article in journal (Refereed)
    Abstract [en]

    In this paper, a pair of novel rectification algorithms (greedy negative pressure push algorithm and dynamic local stitching algorithm) is proposed to cooperatively repair broken transmitting paths in Wireless Sensor Networks. Our approach is to overcome the poor data validity in WSNs, specifically for harsh application environments - such as unattended sensor nodes or frail wireless transmitting channels - where fault tolerant becomes a vital aspect. Using adjacency information, Greedy negative pressure push algorithm can efficiently grow the transmitting path to achieve the minimum energy consumption for relays model. Here, we measured packet travel time and the expectation of relay distance to set this model's key parameters to achieve the lowest possible end-to-end transmitting delay. Dynamic local stitching algorithm has a major difference with other existing routing algorithms in rectifying broken paths: despite others that reroute whole paths, our algorithms only stitch broken fragments of the original path spending minimum amount of energy as well as recovery time. Based on mathematical computing and simulation, our novel rectification algorithm could effectively (1) reduce the total number of routing overheads, (2) improve net throughput, and (3) increase system fault tolerant much better than four already designed routing algorithms. Results were also very promising to motivate other algorithms in this field.

  • 1039.
    Yang, Ting
    et al.
    School of Electrical and Automation Engineering, Tianjin University, Tianjin.
    Woo, Peng-Yung
    Department of Electrical Engineering, College of Engineering and Engineering Technology, Northern Illinois University.
    Wang, Zhaoxia
    Institute of High Performance Computing, Singapore.
    Taheri, Javid
    The University of Sydney, Australia.
    Choor, Chin Hoong
    Department of Civil and Environmental Engineering, National University of Singapore, Singapore.
    Hu, Guoqiang
    School of Electrical & Electronic Engineering, Nanyang Technology University, Singapore.
    Ubiquitous Data-Centric Sensor Networks2014In: International Journal of Distributed Sensor Networks, ISSN 1550-1329, E-ISSN 1550-1477, Vol. 10, no 4Article in journal (Refereed)
  • 1040.
    Ye, Panming
    et al.
    Karlstad University. Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Zhou, Yong
    Karlstad University. Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Distributed Cross-layer Monitoring in Wireless Mesh Networks2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless mesh networks has rapid development over the last few years. However, due to properties such as distributed infrastructure and interference, which strongly affect the performance of wireless mesh networks, developing technology has to face the challenge of architecture and protocol design issues. Traditional layered protocols do not function efficiently in multi-hop wireless environments. To get deeper understanding on interaction of the layered protocols and optimize the performance of wireless mesh network, more recent researches are focusing on cross-layer measurement schemes and cross-layer protocol design. The goal of this project is to implement a distributed monitoring mechanism for IEEE802.11 based wireless mesh networks. This module is event-based and has modular structure that makes it flexible to be extended. This project results a novel Cross-Layer Monitoring Module, CLMM, which is a prototype that monitors each layer of the nodes locally and dynamically, calculates the average values of the metrics, compares these values with thresholds and handles the cross-layer messages of each node. The CLMM also has a routing module structure that can be extended to distribute the metrics to its neighbors.

  • 1041.
    Yedugundla, Kiran
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Evaluating and Reducing Multipath Transport Latency2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Access to the Internet is a very significant part of everyday life with increasing online services such as news delivery, banking, gaming, audio and high quality movies. Applications require different transport guarantees with some requiring higher bandwidth and others low latency. Upgrading access link capacity does not guarantee faster access to the Internet as it offers higher bandwidth but may not offer low latency. With increasing number of mobile devices supporting more than one access technologies (e.g., WLAN, 3G, 4G,..), there is a need to analyse the impact of using multiple such technologies at the same time. Legacy transport protocols such as TCP or SCTP are only able to connect to one access network at a time to create an end-to-end connection. When more than one access technology is used, there may be a large difference in the data rate offered by each technology. This asymmetry might impact latency sensitive applications by creating out of order delivery. In this thesis, we focus on the latency aspect of multipath transport protocol performance. We consider CMT-SCTP and Multipath TCP as available multipath protocols that were designed for exploiting multiple paths for better throughput and reliability. We consider various real world traffic scenarios such as Video, Gaming and Web traffic to measure end-to-end latency. We perform simulations, emulations and experiments using heterogeneous network settings involving access networks with different bandwidth, delay and loss characteristics. MPTCP performs better in terms of latency than CMT-SCTP and TCP in certain scenarios where available paths are symmetric. However, MPTCP does not perform well in asymmetric scenarios with latency sensitive traffic. This analysis provides insights in to various areas of improvement in MPTCP such as scheduling and loss recovery to achieve low latency. We further focus on packet loss recovery in MPTCP for specific cases of tail losses to reduce latency. Tail losses are the losses that occur at the end of a packet stream. Recovering such losses is of higher significance to latency sensitive applications. We propose a modification to the use of TLP, a mechanism in TCP for tail loss recovery. We evaluate the performance of proposed TLP modification, first using emulations and with real world network experiments. Our results show significant improvements in latency for specific loss scenarios in emulations and up to 50% improvement in experiments.

  • 1042.
    Yedugundla, Kiran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Handling Packet Losses in Cloud-Based Application Traffic2019In: Proceedings of the 9th International Conference on Cloud Computing and Services Science - Volume 1: CLOSER, SciTePress, 2019, p. 111-119Conference paper (Refereed)
    Abstract [en]

    Internet traffic is comprised of data flows from various applications with unique traffic characteristics. For many cloud applications, end-to-end latency is a primary factor affecting the perceived user experience. As packet losses cause delays in the communication they impact user experience, making efficient handling of packet losses an important function of transport layer protocols. Multipath TCP (MPTCP) is a modification to TCP that enables simultaneous use of several paths for a TCP flow. MPTCP is known to improve throughput. However, the performance of MPTCP is not optimal when handling certain loss scenarios. Efficient packet loss recovery is thus important to achieve desirable flow completion times for interactive cloud-based applications. In this paper we evaluate the performance of MPTCP in handling tail losses using traffic traces from various cloud-based applications. Tail losses, losses that occur at the end of a flow or traffic burst, are particularly challenging from a latency perspective as they are difficult to detect and recover in a timely manner. Tail losses in TCP are handled by using a tail loss probe (TLP) mechanism which was adapted to MPTCP from TCP. We investigate the performance of TLP in MPTCP, comparing the standard implementation to a recently proposed, less conservative approach. Our experimental results show that a less conservative implementation of TLP performs significantly better than the standard implementation in handling tail losses, reducing the average burst completion time of cloud based applications when tail loss occurs by up to 50% in certain cases.

  • 1043.
    Ypper, Andreas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Andersson, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Demand responsive transit service module2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 1044.
    Zhang, Ge
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    An analysis for anonymity and unlinkability for a VoIP conversation2009In: PRIVACY AND IDENTITY MANAGEMENT FOR LIFE, 2009, p. 198-212Conference paper (Refereed)
    Abstract [en]

    With the growth of its popularity, more and more VoIP services are deployed in the Internet nowadays. Similarly to other Internet applications, VoIP users may desire to be unlinkable with their participated VoIP session records for privacy issues. In this paper, we explore the Items of Interests (IOIs) from anonymization aspects based on a simplified VoIP model and analyze the potential links between them. We address possible methods to break the links. Finally, we also discuss requirements for a VoIP Anonymization Service (VAS)

  • 1045.
    Zhang, Ge
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Towards Secure SIP Signalling Service for VoIP applications: Performance-related Attacks and Preventions2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Current Voice over IP (VoIP) services are regarded less secure than the traditional public switched telephone network (PSTN). This is due to the fact that VoIP services are frequently deployed in an relatively open environment so that VoIP infrastructures can be easily accessed by potential attackers. Furthermore, current VoIP services heavily rely on other public Internet infrastructures shared with other applications. Thus, the vulnerabilities of these Internet infrastructures can affect VoIP applications as well. Nevertheless, deployed in a closed environment with independent protocols, PSTN has never faced similar risks.

    The main goal of this licentiate thesis is the discussion of security issues of the Session Initiation Protocol (SIP), which serves as a signalling protocol for VoIP services. This work especially concentrates on the security risks of SIP related to performance. These risks can be exploited by attackers in two ways: either actively or passively. The throughput of a SIP proxy can be actively manipulated by attackers to reduce the availability of services. It is defined as Denial of Service (DoS) attacks. On the other hand, attackers can also profile confidential information of services (e.g., calling history) by passively observing the performance of a SIP proxy. It is defined as a timing attack. In this thesis, we carefully studied four concrete vulnerabilities existing in current SIP services, among which, three of them can lead to DoS attacks and one can be exploited for timing attacks. The results of our experiments demonstrate that these attacks can be launched easily in the real applications.

    Moreover, this thesis discusses different countermeasure solutions for the attacks respectively. The defending solutions have all in common that they are influencing the performance, by either enhancing the performance of the victim during a DoS attack, or abating the performance to obscure the time characteristic for a timing attack. Finally, we carefully evaluated these solutions with theoretical analyses and concrete experiments.

  • 1046.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Berthold, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Hidden VoIP Calling Records from Networking Intermediaries2010Conference paper (Refereed)
    Abstract

    While confidentiality of telephone conversation contents has recently received considerable attention in Internet telephony (VoIP), the protection of the caller--callee relation is largely unexplored. From the privacy research community we learn that this relation can be protected by Chaum's mixes. In early proposals of mix networks, however, it was reasonable to assume that high latency is acceptable. While the general idea has been deployed for low latency networks as well, important security measures had to be dropped for achieving performance. The result is protection against a considerably weaker adversary model in exchange for usability. In this paper, we show that it is unjustified to conclude that low latency network applications imply weak protection. On the contrary, we argue that current Internet telephony protocols provide a range of promising preconditions for adopting anonymity services with security properties similar to those of high latency anonymity networks. We expect that implementing anonymity services becomes a major challenge as customer privacy becomes one of the most important secondary goals in any (commercial) Internet application.

  • 1047.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Cheng, Feng
    Meinel, Christoph
    SIMPA: A SIP-based Mobile Payment Architecture2008Conference paper (Refereed)
    Abstract [en]

    In recent years, many mobile payment (MP) schemes have been proposed and used in practise. However, a prerequisite for extended acceptance and adoption of MP technologies is to deploy an effective MP system. So far, there is no such a standardised and scalable MP platform. Most current MP schemes are circumscribed by its mobile network infrastructures. Fortunately, the fast advancement of 3G technology equips next generation mobile phone network more benefits. Following this direction, we propose SIMPA - A SIP-based Mobile Payment Architecture for next generation mobile network, which not only supports P2P payment communications between customers and merchants using Session Initiation Protocol (SIP), but also supports several traditional Internet security protocols, to enhance privacy, confidentiality and integrity during the transaction. This paper depicts detailed protocol and system architecture of SIMPA. Some application examples from customers' view are shown to demonstrate its function and feature

  • 1048.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Cheng, Feng
    Meinel, Christoph
    Towards Secure Mobile Payment Based on SIP2008Conference paper (Refereed)
    Abstract [en]

    Mobile payment has some unique advantages over more traditional payment methods in, for example, TV shopping and mobile multimedia services. Unfortunately, most existing mobile payment solutions rely heavily on underlying communication infrastructures, which are platform-dependent and have no unified implementation criteria. This limitation is reducing, however, through the rapid spread of the Voice over IP (VoIP) telephony service and its integration with mobile phones. The Session Initiation Protocol (SIP) is currently the standard signalling protocol of VoIP. Mobile payment is expected to be implemented and deployed in an SIP environment in order to keep pace with the evolution of the mobile phone network. The goal of this paper is firstly to propose a new mobile payment scheme based on SIP. The protocol of the proposed framework is thoroughly analysed. Secondly, we evaluate security issues and propose enhanced solutions to make this new framework applicable in practise

  • 1049.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Peer-to-Peer VoIP Communications Using Anonymisation Overlay Networks2010In: Communications and Multimedia Security: Proceedings of the 11th IFIP TC 6/TC 11, CMS2010, international conference on Communications and Multimedia Security / [ed] De Decker, Bart; Schaumüller-Bichl, Ingrid, Berlin: Springer , 2010, p. 130-141Conference paper (Refereed)
    Abstract [en]

    Nowadays, Voice over Internet Protocol (VoIP) which enables voice conversation remotely over packet switched networks gains much attentions for its low costs and flexible services. However, VoIP calling anonymity, particularly to withhold who called whom, is difficult to achieve since VoIP infrastructures are usually deployed in an open networking environment (e.g., the Internet). Our work studies an anonymisation overlay network (AON) based solution to prevent surveillance from external attackers, who are able to wiretap the communication channels as well as to manipulate voice packets in the channels. However, it has been demonstrated that the VoIP combined with traditional AONs are vulnerable to two attacks, namely watermark attack and complementary matching attack. Taking these two attacks into account, we investigate the defensive dropping method in VoIP: A VoIP user-agent sends packets to an AON in a constant rate, but packets during periods of silence are marked. Then, the AON drops some silence packets and forwards the remaining ones to their destinations. The result of our experiments shows that the dropping rate must be carefully selected to counteract both of the two attacks. Finally, we discuss further threats in terms of this solution

  • 1050.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Bezzi, Michele
    Duquenoy, Penny
    Hansen,, Marit
    Privacy and Identity Management for Life: 5th IFIP primelife international summer school revised selected papers2010Conference paper (Refereed)
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