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The European General Data Protection Regulation requires the implementation of Technical and Organizational Measures (TOMs) to reduce the risk of illegitimate processing of personal data. For these measures to be effective, they must be applied correctly by employees who process personal data under the authority of their organization. However, even data processing employees often have limited knowledge of data protection policies and regulations, which increases the likelihood of misconduct and privacy breaches. To lower the likelihood of unintentional privacy breaches, TOMs must be developed with employees’ needs, capabilities, and usability requirements in mind. To reduce implementation costs and help organizations and IT engineers with the implementation, privacy patterns have proven to be effective for this purpose. In this chapter, we introduce the privacy pattern Data Cart, which specifically helps to develop TOMs for data processing employees. Based on a user-centered design approach with employees from two public organizations in Germany, we present a concept that illustrates how Privacy by Design can be effectively implemented. Organizations, IT engineers, and researchers will gain insight on how to improve the usability of privacy-compliant tools for managing personal data.
Is It Really You Who Forgot the Password? When Account Recovery Meets Risk-Based Authentication
(2024)
Der Programmier-Trainingsplan für alle, die weiter kommen wollen.
In diesem Übungsbuch trainierst du anhand von kurzweiligen und praxisnahen Aufgaben deine Programmierfähigkeiten. Jedes Kapitel beginnt mit einem kurzen Warmup zum behandelten Programmierkonzept; die Umsetzung übst du dann anhand von zahlreichen Workout-Aufgaben. Du startest mit einfachen Aufgaben und steigerst dich hin zu komplexeren Fragestellungen. Damit dir nicht langweilig wird, gibt es über 150 praxisnahe Übungen. So lernst du z. B. einen BMI-Rechner oder einen PIN-Generator zu programmieren oder wie du eine Zeitangabe mit einer analogen Uhr anzeigen kannst. (Verlagsangaben)
Risikobasierte Authentifizierung (RBA) ist ein adaptiver Ansatz zur Stärkung der Passwortauthentifizierung. Er überwacht eine Reihe von Merkmalen, die sich auf das Loginverhalten während der Passworteingabe beziehen. Wenn sich die beobachteten Merkmalswerte signifikant von denen früherer Logins unterscheiden, fordert RBA zusätzliche Identitätsnachweise an. Regierungsbehörden und ein Erlass des US-Präsidenten empfehlen RBA, um Onlineaccounts vor Angriffen mit gestohlenen Passwörtern zu schützen. Trotz dieser Tatsachen litt RBA unter einem Mangel an offenem Wissen. Es gab nur wenige bis keine Untersuchungen über die Usability, Sicherheit und Privatsphäre von RBA. Das Verständnis dieser Aspekte ist jedoch wichtig für eine breite Akzeptanz.
Diese Arbeit soll ein umfassendes Verständnis von RBA mit einer Reihe von Studien vermitteln. Die Ergebnisse ermöglichen es, datenschutzfreundliche RBA-Lösungen zu schaffen, die die Authentifizierung stärken bei gleichzeitig hoher Menschenakzeptanz.
Risk-Based Authentication for OpenStack: A Fully Functional Implementation and Guiding Example
(2023)
Online services have difficulties to replace passwords with more secure user authentication mechanisms, such as Two-Factor Authentication (2FA). This is partly due to the fact that users tend to reject such mechanisms in use cases outside of online banking. Relying on password authentication alone, however, is not an option in light of recent attack patterns such as credential stuffing.
Risk-Based Authentication (RBA) can serve as an interim solution to increase password-based account security until better methods are in place. Unfortunately, RBA is currently used by only a few major online services, even though it is recommended by various standards and has been shown to be effective in scientific studies. This paper contributes to the hypothesis that the low adoption of RBA in practice can be due to the complexity of implementing it. We provide an RBA implementation for the open source cloud management software OpenStack, which is the first fully functional open source RBA implementation based on the Freeman et al. algorithm, along with initial reference tests that can serve as a guiding example and blueprint for developers.
Digital ecosystems are driving the digital transformation of business models. Meanwhile, the associated processing of personal data within these complex systems poses challenges to the protection of individual privacy. In this paper, we explore these challenges from the perspective of digital ecosystems' platform providers. To this end, we present the results of an interview study with seven data protection officers representing a total of 12 digital ecosystems in Germany. We identified current and future challenges for the implementation of data protection requirements, covering issues on legal obligations and data subject rights. Our results support stakeholders involved in the implementation of privacy protection measures in digital ecosystems, and form the foundation for future privacy-related studies tailored to the specifics of digital ecosystems.
Login Data Set for Risk-Based Authentication
Synthesized login feature data of >33M login attempts and >3.3M users on a large-scale online service in Norway. Original data collected between February 2020 and February 2021.
This data sets aims to foster research and development for <a href="https://riskbasedauthentication.org">Risk-Based Authentication (RBA) systems. The data was synthesized from the real-world login behavior of more than 3.3M users at a large-scale single sign-on (SSO) online service in Norway.
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.
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.
Risk-based authentication (RBA) aims to protect users against attacks involving stolen passwords. RBA monitors features during login, and requests re-authentication when feature values widely differ from those previously observed. It is recommended by various national security organizations, and users perceive it more usable than and equally secure to equivalent two-factor authentication. Despite that, RBA is still used by very few online services. Reasons for this include a lack of validated open resources on RBA properties, implementation, and configuration. This effectively hinders the RBA research, development, and adoption progress.
To close this gap, we provide the first long-term RBA analysis on a real-world large-scale online service. We collected feature data of 3.3 million users and 31.3 million login attempts over more than 1 year. Based on the data, we provide (i) studies on RBA’s real-world characteristics plus its configurations and enhancements to balance usability, security, and privacy; (ii) a machine learning–based RBA parameter optimization method to support administrators finding an optimal configuration for their own use case scenario; (iii) an evaluation of the round-trip time feature’s potential to replace the IP address for enhanced user privacy; and (iv) a synthesized RBA dataset to reproduce this research and to foster future RBA research. Our results provide insights on selecting an optimized RBA configuration so that users profit from RBA after just a few logins. The open dataset enables researchers to study, test, and improve RBA for widespread deployment in the wild.
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.
Die Blockchain-Technologie ist einer der großen Innovationstreiber der letzten Jahre. Mit einer zugrundeliegenden Blockchain-Technologie ist auch der Betrieb von verteilten Anwendungen, sogenannter Decentralized Applications (DApps), bereits technisch umsetzbar. Dieser Beitrag verfolgt das Ziel, Gestaltungsmöglichkeiten der digitalen Verbraucherteilhabe an Blockchain-Anwendungen zu untersuchen. Hierzu enthält der Beitrag eine Einführung in die digitale Verbraucherteilhabe und die technischen Grundlagen und Eigenschaften der Blockchain-Technologie, einschließlich darauf basierender DApps. Abschließend werden technische, ethisch-organisatorische, rechtliche und sonstige Anforderungsbereiche für die Umsetzung von digitaler Verbraucherteilhabe in Blockchain-Anwendungen adressiert.
Risk-based authentication (RBA) extends authentication mechanisms to make them more robust against account takeover attacks, such as those using stolen passwords. RBA is recommended by NIST and NCSC to strengthen password-based authentication, and is already used by major online services. Also, users consider RBA to be more usable than two-factor authentication and just as secure. However, users currently obtain RBA's high security and usability benefits at the cost of exposing potentially sensitive personal data (e.g., IP address or browser information). This conflicts with user privacy and requires to consider user rights regarding the processing of personal data. We outline potential privacy challenges regarding different attacker models and propose improvements to balance privacy in RBA systems. To estimate the properties of the privacy-preserving RBA enhancements in practical environments, we evaluated a subset of them with long-term data from 780 users of a real-world online service. Our results show the potential to increase privacy in RBA solutions. However, it is limited to certain parameters that should guide RBA design to protect privacy. We outline research directions that need to be considered to achieve a widespread adoption of privacy preserving RBA with high user acceptance.
Components and Architecture for the Implementation of Technology-Driven Employee Data Protection
(2021)
In Fortführung zu den drei erfolgreichen „Usable Security und Privacy“ Workshops der letzten drei Jahre, sollen in einem vierten ganztätigen wissenschaftlichen Workshop auf der diesjährigen Mensch und Computer sechs bis acht Arbeiten auf dem Gebiet Usable Security and Privacy vorgestellt und diskutiert werden. Vorgesehen sind Beiträge aus Forschung und Praxis, die neue nutzerzentrierte Ansätze aber auch praxisrelevante Lösungen zur nutzerzentrierten Entwicklung und Ausgestaltung von digitalen Schutzmechanismen thematisieren. Mit dem Workshop soll das etablierte Forum weiterentwickelt werden, in dem sich Experten aus unterschiedlichen Domänen, z. B. dem Usability-Engineering und Security-Engineering, transdisziplinär austauschen können. Der Workshop wird von den Organisatoren als klassischer wissenschaftlicher Workshop ausgestaltet. Ein Programmkomitee bewertet die Einreichungen und wählt daraus die zur Präsentation akzeptierten Beiträge aus. Diese werden zudem im Poster- und Workshopband der Mensch und Computer 2018 veröffentlicht.
Recent years have seen extensive adoption of domain generation algorithms (DGA) by modern botnets. The main goal is to generate a large number of domain names and then use a small subset for actual C&C communication. This makes DGAs very compelling for botmasters to harden the infrastructure of their botnets and make it resilient to blacklisting and attacks such as takedown efforts. While early DGAs were used as a backup communication mechanism, several new botnets use them as their primary communication method, making it extremely important to study DGAs in detail.
In this paper, we perform a comprehensive measurement study of the DGA landscape by analyzing 43 DGAbased malware families and variants. We also present a taxonomy for DGAs and use it to characterize and compare the properties of the studied families. By reimplementing the algorithms, we pre-compute all possible domains they generate, covering the majority of known and active DGAs. Then, we study the registration status of over 18 million DGA domains and show that corresponding malware families and related campaigns can be reliably identified by pre-computing future DGA domains. We also give insights into botmasters’ strategies regarding domain registration and identify several pitfalls in previous takedown efforts of DGA-based botnets. We will share the dataset for future research and will also provide a web service to check domains for potential DGA identity.
Helping Johnny to Analyze Malware: A Usability-Optimized Decompiler and Malware Analysis User Study
(2016)
Der Arbeitskreis Usable Security & Privacy bietet ein Forum für den Gedankenaustausch und die interdisziplinäre Zusammenarbeit rund um das Thema benutzerfreundliche Informationssicherheit und privatheitsfördernde Technologien. Sicherheit ist bei der Anschaffung von Software und Technikprodukten zwar eines der zentralen Auswahlkriterien – aufgrund mangelnder Gebrauchstauglichkeit werden die vorhandenen Sicherheitsfunktionen und -mechanismen von den Nutzern jedoch oft falsch oder überhaupt nicht bedient. Im alltäglichen Gebrauch ergeben sich hierdurch Sicherheitsgefährdungen beim Umgang mit IKT-Systemen bzw. -Produkten und den darin enthaltenen sensiblen Daten. Im Workshop werden mit den Teilnehmern Beispiele diskutiert und es wird gemeinsam ein Stimmungsbild zum Verständnis, zum Stellenwert und zum aktuellen Grad der Umsetzung von Usable Security & Privacy erhoben. Ergebnis des Workshops ist ein Positionspapier, in dem die aktuellen Problemfelder und die wichtigsten Herausforderungen aus Sicht der Usability und UX Professionals beschrieben sind.
In Fortführung zum erfolgreichen Auftaktworkshop „Usable Security and Privacy: Nutzerzentrierte Lösungsansätze zum Schutz sensibler Daten“ auf der Mensch und Computer 2015 werden in einem zweiten wissenschaftlichen Workshop auf der diesjährigen Mensch und Computer vier Arbeiten auf dem Gebiet Usable Security and Privacy vorgestellt und diskutiert. Das Programm bilden Beiträge aus Forschung und Praxis, die neue nutzerzentrierte Ansätze, aber auch praxisrelevante Lösungen zur nutzerzentrierten Entwicklung und Ausgestaltung von digitalen Schutzmechanismen thematisieren. Mit dem Workshop wird das etablierte Forum weiterentwickelt, in dem sich Experten aus unterschiedlichen Domänen, z. B. dem Usability-Engineering und Security-Engineering, transdisziplinär austauschen können. Der Workshop wird von den Organisatoren als klassischer wissenschaftlicher Workshop ausgestaltet. Ein Programmkomitee hat die Einreichungen bewertet und daraus die zur Präsentation akzeptierten Beiträge ausgewählt.
In education, finding the appropriate learning pace that fits to the members of a large group is a challenging task. This becomes especially evident when teaching multidisciplinary subjects such as epidemiology in medicine or computer science in most study programs, since lecturers have to face a very heterogeneous state of previous knowledge. Approaching this issue requires an individual supervision of each and every student, which is obviously bounded by the available resources. Moreover, when referring back to the second example, writing computer programs requires a complex installation and configuration of development tools. Many beginning programmers already become stuck at this entry stage. This paper introduces WHELP, a Web-based Holistic E-Learning Platform, which provides an integrated environment enabling the learning and teaching of computer science topics without the need to install any software. Moreover, WHELP includes an interactive feedback system for each programming exercise, where lecturers or tutors can supply comments, improvements, code assistance or tips helping the students to accomplish their tasks. Furthermore, WHELP offers a statistical analysis module as well as a real-time classroom polling system both promoting an overview of the state of knowledge of a course. In addition to that, WHELP enables collaborative working including code-sharing and peer-to-peer learning. This feature enables students to work on exercises simultaneously at distinct places. WHELP has been successfully deployed in the winter term 2013 at the Cologne University of Applied Sciences supporting the 120 students and 3 lecturers to learn and teach basic topics of computer science in an engineering study program.
Botnets
(2013)
Malware poses one of the major threats to all currently operated computer systems. The scale of the problem becomes obvious by looking at the global economic loss caused by different kinds of malware, which is estimated to be more than US$ 10 billion every year. Botnets, a special kind of malware, are used to reap economic gains by criminals as well as for politically motivated activities. In contrast to other kinds of malware, botnets utilize a hidden communication channel to receive commands from their operator and communicate their current status. The ability to execute almost arbitrary commands on the infected machines makes botnets a general-purpose tool to perform malicious cyber-activities. (Verlagsangaben)
XML Encryption and XML Signature are fundamental security standards forming the core for many applications which require to process XML-based data. Due to the increased usage of XML in distributed systems and platforms such as in SOA and Cloud settings, the demand for robust and effective security mechanisms increased as well. Recent research work discovered, however, substantial vulnerabilities in these standards as well as in the vast majority of the available implementations. Amongst them, the so-called XML Signature Wrapping attack belongs to the most relevant ones. With the many possible instances of this attack type, it is feasible to annul security systems relying on XML Signature and to gain access to protected resources as has been successfully demonstrated lately for various Cloud infrastructures and services. This paper contributes a comprehensive approach to robust and effective XML Signatures for SOAP-based Web Services. An architecture is proposed, which integrates the r equired enhancements to ensure a fail-safe and robust signature generation and verification. Following this architecture, a hardened XML Signature library has been implemented. The obtained evaluation results show that the developed concept and library provide the targeted robustness against all kinds of known XML Signature Wrapping attacks. Furthermore the empirical results underline, that these security merits are obtained at low efficiency and performance costs as well as remain compliant with the underlying standards.
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 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.
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.
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.
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.
The @neurIST project
(2008)
This work introduces Grid computing, showsits use in eHealth environments and elicits trends towards the integration of custodians in eHealth Grids. It considers security and privacy requirements for the use of Grid computing in eHealth scenariosand discusses the possible integration of different types of data custodians. Finally the paper concludes and gives an outlook on the development and deployment of eHealth Gridsinthe near future.
Das Auslesen von Messdaten in elektronischer Form ermöglicht es, diese vom Ursprung bis zur Rechnungsstellung effizient und ohne Medienbruch zu erheben und zu verarbeiten. Gerade im liberalisierten Energiemarkt ist dies von Bedeutung, da eine Vielzahl von Marktteilnehmern miteinander kommunizieren muss. Das im VERNET-Programm geförderte SELMA-Projekt verfolgt das Ziel, einen Standard für den sicheren elektronischen Austausch von Messdaten zu entwickeln und zu etablieren. Eine der zentralen Anforderungen ist die Gewährleistung der Authentizität und Integrität der über offene Netze ausgelesenen Messdaten, die über die gesamte Lebensdauer der Messdaten nachprüfbar sein sollen. Die technische Umsetzung dieser Anforderungen resultiert in einer Sicherheitsarchitektur, die durch den durchgängigen Einsatz elektronischer Signaturen gekennzeichnet ist. Mit den signierten Datensätzen können die Rechnungen von den Marktteilnehmern auf ihre Authentizität und Integrität hin überprüft werden. Dieser Beitrag zeigt die gesetzgeberischen Hindernisse auf, die bei der Umsetzung der Anforderungen an qualifizierte Signaturen im elektronischen Messdatenaustausch auftreten und wie dennoch eine größtmögliche Beweiskraft für fortgeschrittene Signaturen erreicht werden kann.
Echtzeit-orientierte Multimedia-Kommunikation im Internet eröffnet eine Vielzahl neuer Anwendungen. Diese innovative Kommunikationsplattform ist gerade für weltweit operierende Unternehmen von Interesse. So können z.B. durch die Verwendung von VoIP-Lösungen oder Groupware-Applikationen Kosten gesenkt und gleichzeitig die Zusammenarbeit der Mitarbeiter optimiert werden. Dies trifft auch für Video-Konferenzsysteme zu. Anstelle regelmäßiger Meetings, die meist mit Dienstreisen eines Großteils der Teilnehmer verbunden sind, können Konferenzen virtuell durch die Übertragung von Sprachund Videodaten über das Internet abgehalten werden. Die Akzeptanz der beschriebenen Kommunikationsanwendungen hängt stark von den Faktoren Dienstgüte und Sicherheit ab. Die Übertragung der echtzeit-orientierten Mediendaten muss möglichst kontinuierlich erfolgen, so dass sowohl eine ruckelfreie Wiedergabe der Sprache als auch der Bewegtbilder möglich ist. Da Konferenzen firmenintern und vertraulich sind, werden sie hinter verschlossener Tür abgehalten. Das Pendant in der elektronischen Welt muss eine Entsprechung anbieten. Se- curity-Mechanismen haben allerdings einen Einfluss auf Dienstgüteparameter. Dies muss bei der Entwicklung von Techniken zum Schutz multimedialer Kommunikation berücksichtigt und abgestimmt werden. Dieser Beitrag zeigt anhand des Beispiels eines Video-Konferenzsystems für das Internet, wie Sicherheitsmechanismen in echtzeit-orientierte Multimedia-Kommunikationsanwendungen unter Berücksichtigung von Quality of Service (QoS) integriert werden können.
Software developers build complex systems using plenty of third-party libraries. Documentation is key to understand and use the functionality provided via the libraries’ APIs. Therefore, functionality is the main focus of contemporary API documentation, while cross-cutting concerns such as security are almost never considered at all, especially when the API itself does not provide security features. Documentations of JavaScript libraries for use in web applications, e.g., do not specify how to add or adapt a Content Security Policy (CSP) to mitigate content injection attacks like Cross-Site Scripting (XSS). This is unfortunate, as security-relevant API documentation might have an influence on secure coding practices and prevailing major vulnerabilities such as XSS. For the first time, we study the effects of integrating security-relevant information in non-security API documentation. For this purpose, we took CSP as an exemplary study object and extended the official Google Maps JavaScript API documentation with security-relevant CSP information in three distinct manners. Then, we evaluated the usage of these variations in a between-group eye-tracking lab study involving N=49 participants. Our observations suggest: (1) Developers are focused on elements with code examples. They mostly skim the documentation while searching for a quick solution to their programming task. This finding gives further evidence to results of related studies. (2) The location where CSP-related code examples are placed in non-security API documentation significantly impacts the time it takes to find this security-relevant information. In particular, the study results showed that the proximity to functional-related code examples in documentation is a decisive factor. (3) Examples significantly help to produce secure CSP solutions. (4) Developers have additional information needs that our approach cannot meet.
Overall, our study contributes to a first understanding of the impact of security-relevant information in non-security API documentation on CSP implementation. Although further research is required, our findings emphasize that API producers should take responsibility for adequately documenting security aspects and thus supporting the sensibility and training of developers to implement secure systems. This responsibility also holds in seemingly non-security relevant contexts.
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.
Privatheit am Arbeitsplatz
(2020)
Listen to Developers! A Participatory Design Study on Security Warnings for Cryptographic APIs
(2020)
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.
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).
Kontemporäre Service-orientierte Systeme sind hochgradig vernetzt und haben zudem die Eigenschaft massiv-skalierbar zu sein. Diese Charakteristiken stellen im besonderen Maße Anforderungen an die Datensicherheit der Anwender solcher Systeme und damit primär an alle Stakeholder der Softwareentwicklung, die in der Verantwortung sind, passgenaue Sicherheitsmechanismen effektiv in die Softwareprodukte zu bringen. Die Effektivität von Sicherheitsarchitekturen in service-orientierten Systemen hängt maßgeblich von der richtigen Nutzung und Integration von Security-APIs durch eine heterogene Gruppe von Softwareentwicklern ab, bei der nicht per se ein fundiertes Hintergrundwissen über komplexe digitale Sicherheitsmechanismen vorausgesetzt werden kann. Die Diskrepanz zwischen komplexen und in der Anwendung fehleranfälligen APIs und einem fehlenden Verständnis für die zugrundeliegenden Sicherheitskonzepte auf Seiten der Nutzer begünstigt in der Praxis unsichere Softwaresysteme. Aus diesem Grund ist die Gebrauchstauglichkeit von Security-APIs besonders relevant, damit Programmierer den benötigten Funktionsumfang effektiv, effizient und zufriedenstellend verwenden können. Abgeleitet von dieser Problemstellung, konzentriert sich das Dissertationsvorhaben auf die gebrauchstaugliche Ausgestaltung von Security-APIs und den Herausforderungen die sich aus den Methoden zur Evaluation der Usability in typischen Umgebungen der Softwareentwicklung ergeben.