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Ziel der neunten Ausgabe des wissenschaftlichen Workshops "Usable Security und Privacy" auf der Mensch und Computer 2023 ist es, aktuelle Forschungs- und Praxisbeiträge auf diesem Gebiet zu präsentieren und mit den Teilnehmer:innen zu diskutieren. Getreu dem Konferenzmotto "Building Bridges" soll mit dem Workshop ein etabliertes Forum fortgeführt und weiterentwickelt werden, in dem sich Expert:innen, Forscher:innen und Praktiker:innen aus unterschiedlichen Domänen transdisziplinär zum Thema Usable Security und Privacy austauschen können. Das Thema betrifft neben dem Usability- und Security-Engineering unterschiedliche Forschungsgebiete und Berufsfelder, z. B. Informatik, Ingenieurwissenschaften, Mediengestaltung und Psychologie. Der Workshop richtet sich an interessierte Wissenschaftler:innen aus all diesen Bereichen, aber auch ausdrücklich an Vertreter:innen der Wirtschaft, Industrie und öffentlichen Verwaltung.
In recent years a new category of digital signature algorithms based on Elliptic Curve Cryptography (ECC) has taken place besides well known schemes as RSA or DSA. So far it is, however, still not obvious how ECC-based signature schemes can be integrated in X.509-based Public Key Infrastructures (PKI).This paper briefly introduces cryptographic basics of signature schemes based on elliptic curves and points out the necessary cryptography parameters that are important in this context. Afterwards the structure and the encoding of X.509 certificates and Certificate Revocation Lists (CRL) are discussed regarding the integration of ECC public keys and ECC signatures respectively. The paper closes with exemplary implementations of ECC-based security systems.
Data transfer and staging services are common components in Grid-based, or more generally, in service-oriented applications. Security mechanisms play a central role in such services, especially when they are deployed in sensitive application fields like e-health. The adoption of WS-Security and related standards to SOAP-based transfer services is, however, problematic as a straightforward adoption of SOAP with MTOM introduces considerable inefficiencies in the signature generation process when large data sets are involved. This paper proposes a non-blocking, signature generation approach enabling a stream-like processing with considerable performance enhancements.
The @neurIST project
(2008)
This paper presents the security architecture of the @neurIST medical information system. @neurIST aims at a research and decision support system for treating diseases that unites multiple medical institutions and service providers offering technical solutions based on the Service Oriented Architecture (SOA) paradigm. The security architecture provides secure access to federated medical data spread across multiple sites and protects the privacy of the patients by pseudonymisation of the medical data required for the study.
Auch die mittlerweile siebte Ausgabe des wissenschaftlichen Workshops “Usable Security und Privacy” auf der Mensch und Computer 2021 wird aktuelle Forschungs- und Praxisbeiträge präsentiert und anschließend mit allen Teilnehmer:innen diskutiert. Zwei Beiträge befassen sich dieses Jahr mit dem Thema Privatsphäre, zwei mit dem Thema Sicherheit. Mit dem Workshop wird ein etabliertes Forum fortgeführt und weiterentwickelt, in dem sich Expert:innen aus unterschiedlichen Domänen, z. B. dem Usability- und Security- Engineering, transdisziplinär austauschen können.
We present a systematization of usable security principles, guidelines and patterns to facilitate the transfer of existing knowledge to researchers and practitioners. Based on a literature review, we extracted 23 principles, 11 guidelines and 47 patterns for usable security and identified their interconnection. The results indicate that current research tends to focus on only a subset of important principles. The fact that some principles are not yet addressed by any design patterns suggests that further work on refining these patterns is needed. We developed an online repository, which stores the harmonized principles, guidelines and patterns. The tool enables users to search for relevant guidance and explore it in an interactive and programmatic manner. We argue that both the insights presented in this article and the web-based repository will be highly valuable for students to get a good overview, practitioners to implement usable security and researchers to identify areas of future research.
Usable Security und Privacy
(2010)
When entering a password (or other secrets) the typed input is most commonly masked, i.e. the characters are hidden behind bullets or asterisks. This, however, complicates the input and highly decreases the user's confident causing several issues such as login failure attempts. On the other hand, password masking is an important security requirement for a lot of applications and contexts to prevent a third person to read the password. Thus, simply dropping password masking is not feasible in general. A common solution provides the user with the choice of toggling password masking on and off, but due to distinct defaults (in dependency of the application and context) this is rather complex and confusing. Enhanced password visualization technologies beyond the simple masking of passwords can provide more sophisticated solutions from both a usability and security perspective. In this paper, available password visualization technologies are presented and discussed. Furthermore a novel password visualization approach is introduced, the TransparentMask, which provides unique properties in comparison to the existing schemes. Amongst these are the ability to detect mistakes while typing and being able to localize and correct the typo within a certain range. Finally, a security analysis of the TransparentMask shows that the protection level given by a certain password length is slightly decreased in comparison to the fully masked approach.
Fast täglich werden neue Angriffe auf IT-Systeme bekannt, bei denen sensible Daten entwendet werden. Das vorliegende Buch vermittelt die wesentlichen Grundlagen und Technologien, die zur Absicherung von Computernetzwerken benötigt werden. Stets legen die Autoren dabei Wert auf eine verständliche Darstellung, die – soweit möglich – auf abstrakte Modelle und formalen Notationen verzichtet. Zu jedem Kapitel werden Aufgaben zur Kontrolle von Wissensstand und Verständnis angeboten.
The usage of the Web has experienced a vertiginous growth in the last few years. Watching video online has been one major driving force for this growth lately. Until the appearance of the HTML5 agglomerate of (still draft) specifications, the access and consumption of multimedia content in the Web has not been standardized. Hence, the use of proprietary Web browser plugins flourished as intermediate solution. With the introduction of the HTML5 VideoElement, Web browser plugins are replaced with a standardized alternative. Still, HTML5 Video is currently limited in many respects, including the access to only file-based media. This paper investigates on approaches to develop video live streaming solutions based on available Web standards. Besides a pull-based design based on HTTP, a push-based architecture is introduced, making use of the WebSocket protocol being part of the HTML5 standards family as well. The evaluation results of both conceptual principles emphasize, that push-based approaches have a higher potential of providing resource and cost efficient solutions as their pull-based counterparts. In addition, initial approaches to instrument the proposed push-based architecture with adaptiveness to network conditions have been developed.
SOA-Readiness of REST
(2014)
Service Security Revisited
(2014)
The Web has become an indispensable prerequisite of everyday live and the Web browser is the most used application on a variety of distinct devices. The content delivered by the Web has changed drastically from static pages to media-rich and interactive Web applications offering nearly the same functionality as native applications, a trend which is further pushed by the Cloud and more specifically the Cloud’s SaaS layer. In the light of this development, security and performance of Web browsing has become a crucial issue.
Usable Security – Benutzerfreundliche Sicherheitsfunktionen für Software und interaktive Produkte
(2017)
Sowohl im geschäftlichen wie im privaten Umfeld müssen Software, Apps und vernetzte Technikprodukte mit Sicherheitsfunktionen ausgestattet sein, die auch für Laien und Gelegenheitsnutzer verständlich und benutzbar sind. Im Umgang mit sensiblen Daten können sich diese Produkte ansonsten schnell als Risiko entpuppen, etwa wenn Sicherheitsmechanismen aufgrund mangelnder Usability von den Nutzern falsch oder überhaupt nicht bedient werden. Der Begriff „Usable Security“ bezeichnet ein Qualitätsmerkmal bzw. einen Entwicklungsansatz für Sicherheitskomponenten von Software und technischen Produkten, in dessen Zentrum der Benutzer steht. Dieser Beitrag soll als Einführung in das Thema Usable Security dienen und zugleich für die Probleme bei der Entwicklung gebrauchstauglicher Sicherheitsfunktionen sensibilisieren. Er ist Teil einer Serie von insgesamt drei Artikeln. Die folgenden zwei Beiträge vertiefen spezifische Themen im Kontext der Entwicklung von Sicherheitsfunktionen auf Grundlage von Muster lösungen (Patterns) und der Ausgestaltung von Warnhinweisen.
The ongoing digitisation in everyday working life means that ever larger amounts of personal data of employees are processed by their employers. This development is particularly problematic with regard to employee data protection and the right to informational self-determination. We strive for the use of company Privacy Dashboards as a means to compensate for missing transparency and control. For conceptual design we use among other things the method of mental models. We present the methodology and first results of our research. We highlight the opportunities that such an approach offers for the user-centred development of Privacy Dashboards.
The processing of employees’ personal data is dramatically increasing, yet there is a lack of tools that allow employees to manage their privacy. In order to develop these tools, one needs to understand what sensitive personal data are and what factors influence employees’ willingness to disclose. Current privacy research, however, lacks such insights, as it has focused on other contexts in recent decades. To fill this research gap, we conducted a cross-sectional survey with 553 employees from Germany. Our survey provides multiple insights into the relationships between perceived data sensitivity and willingness to disclose in the employment context. Among other things, we show that the perceived sensitivity of certain types of data differs substantially from existing studies in other contexts. Moreover, currently used legal and contextual distinctions between different types of data do not accurately reflect the subtleties of employees’ perceptions. Instead, using 62 different data elements, we identified four groups of personal data that better reflect the multi-dimensionality of perceptions. However, previously found common disclosure antecedents in the context of online privacy do not seem to affect them. We further identified three groups of employees that differ in their perceived data sensitivity and willingness to disclose, but neither in their privacy beliefs nor in their demographics. Our findings thus provide employers, policy makers, and researchers with a better understanding of employees’ privacy perceptions and serve as a basis for future targeted research
on specific types of personal data and employees.
Ziel der achten Auflage des wissenschaftlichen Workshops “Usable Security and Privacy” auf der Mensch und Computer 2022 ist es, aktuelle Forschungs- und Praxisbeiträge zu präsentieren und anschließend mit den Teilnehmenden zu diskutieren. Der Workshop soll ein etabliertes Forum fortführen und weiterentwickeln, in dem sich Experten aus verschiedenen Bereichen, z. B. Usability und Security Engineering, transdisziplinär austauschen können.
Dieses Buch führt Sie umfassend in die WebSocket-Technik und die damit einhergehenden neuen Entwicklungsmöglichkeiten ein. Unter den zahlreichen exemplarischen Anwendungen finden sich Beispiele auf Basis von Node.js, Vert.x, und JSR 356, als Programmiersprachen werden Java und JavaScript eingesetzt.
Contemporary software is inherently distributed. The principles guiding the design of such software have been mainly manifested by the service-oriented architecture (SOA) concept. In a SOA, applications are orchestrated by software services generally operated by distinct entities. Due to the latter fact, service security has been of importance in such systems ever since. A dominant protocol for implementing SOA-based systems is SOAP, which comes with a well-elaborated security framework. As an alternative to SOAP, the architectural style representational state transfer (REST) is gaining traction as a simple, lightweight and flexible guideline for designing distributed service systems that scale at large. This paper starts by introducing the basic constraints representing REST. Based on these foundations, the focus is afterwards drawn on the security needs of REST-based service systems. The limitations of transport-oriented protection means are emphasized and the demand for specific message-oriented safeguards is assessed. The paper then reviews the current activities in respect to REST-security and finds that the available schemes are mostly HTTP-centered and very heterogeneous. More importantly, all of the analyzed schemes contain vulnerabilities. The paper contributes a methodology on how to establish REST-security as a general security framework for protecting REST-based service systems of any kind by consistent and comprehensive protection means. First adoptions of the introduced approach are presented in relation to REST message authentication with instantiations for REST-ful HTTP (web/cloud services) and REST-ful constraint application protocol (CoAP) (internet of things (IoT) services).
Despite the lack of standardisation for building REST-ful HTTP applications, the deployment of REST-based Web Services has attracted an increased interest. This gap causes, however, an ambiguous interpretation of REST and induces the design and implementation of REST-based systems following proprietary approaches instead of clear and agreed upon definitions. Issues arising from these shortcomings have an influence on service properties such as the loose coupling of REST-based services via a unitary service contract and the automatic generation of code. To overcome such limitations, at least two prerequisites are required: the availability of specifications for implementing REST-based services and auxiliaries for auditing the compliance of those services with such specifications. This paper introduces an approach for conformance testing of REST-based Web Services. This appears conflicting at the first glance, since there are no specifications available for implementing REST by, e.g., t he prevalent technology set HTTP/URI to test against. Still, by providing a conformance test tool and leaning it on the current practice, the exploration of service properties is enabled. Moreover, the real demand for standardisation gets explorable by such an approach. First investigations conducted with the developed conformance test system targeting major Cloud-based storage services expose inconsistencies in many respects which emphasizes the necessity for further research and standardisation.
Application Programming Interfaces (APIs) are a vital link between software components as well as between software and developers. Security APIs deliver crucial functionalities for programmers who see themselves in the increasing need for integrating security services into their software products. The ignorant or incorrect use of Security APIs leads to critical security flaws, as has been revealed by recent security studies. One major reason for this is rooted in usability issues. API Usability research has been deriving recommendations for designing usable APIs in general. Facing the growing relevance of Security APIs, the question arises, whether the observed usability aspects in the general space are already sufficient enough for building usable Security APIs. The currently available findings in the API Usability domain are selective fragments only, though. This still emerging field has not produced a comprehensive model yet. As a consequence, a first contribution of this paper is such a model that provides a consolidated view on the current research coverage of API Usability. On this baseline, the paper continues by conducting an analysis of relevant security studies, which give insights on usability problems developers had, when using Security APIs. This analysis leads to a proposal of eleven specific usability characteristics relevant for Security APIs. These have to be followed up by usability studies in order to evaluate how Security APIs need to be designed in a usable way and which potential trade-offs have to be balanced.
Online media consumption is the main driving force for the recent growth of the Web. As especially realtime media is becoming more and more accessible from a wide range of devices, with contrasting screen resolutions, processing resources and network connectivity, a necessary requirement is providing users with a seamless multimedia experience at the best possible quality, henceforth being able to adapt to the specific device and network conditions. This paper introduces a novel approach for adaptive media streaming in the Web. Despite the pervasive pullbased designs based on HTTP, this paper builds upon a Web-native push-based approach by which both the communication and processing overheads are reduced significantly in comparison to the pull-based counterparts. In order to maintain these properties when enhancing the scheme by adaptation features, a server-side monitoring and control needs to be developed as a consequence. Such an adaptive push-based media streaming approach is intr oduced as main contribution of this work. Moreover, the obtained evaluation results provide the evidence that with an adaptive push-based media delivery, on the one hand, an equivalent quality of experience can be provided at lower costs than by adopting pull-based media streaming. On the other hand, an improved responsiveness in switching between quality levels can be obtained at no extra costs.