Broadening the Scope of Security Usability from the Individual to the Organizational : Participation and Interaction for Effective, Efficient, and Agile Authorization

Restrictions and permissions in information systems -- Authorization -- can cause problems for those interacting with the systems. Often, the problems materialize as an interference with the primary tasks, for example, when restrictions prevent the efficient completing of work and cause frustration. Conversely, the effectiveness can also be impacted when staff is forced to circumvent the measure to complete work -- typically sharing passwords among each other. This is the perspective of functional staff and the organization. There are further perspectives involved in the administration and development of the authorization measure. For instance, functional staff need to interact with policy makers who decide on the granting of additional permissions, and policy makers, in turn, interact with policy authors who actually implement changes. This thesis analyzes the diverse contexts in which authorization occurs, and systematically examines the problems that surround the different perspectives on authorization in organizational settings. Based on prior research and original research in secure agile development, eight principles to address the authorization problems are identified and explored through practical artifacts

The Transitivity of Trust Problem in the Interaction of Android Applications

Mobile phones have developed into complex platforms with large numbers of installed applications and a wide range of sensitive data. Application security policies limit the permissions of each installed application. As applications may interact, restricting single applications may create a false sense of security for the end users while data may still leave the mobile phone through other applications. Instead, the information flow needs to be policed for the composite system of applications in a transparent and usable manner. In this paper, we propose to employ static analysis based on the software architecture and focused data flow analysis to scalably detect information flows between components. Specifically, we aim to reveal transitivity of trust problems in multi-component mobile platforms. We demonstrate the feasibility of our approach with Android applications, although the generalization of the analysis to similar composition-based architectures, such as Service-oriented Architecture, can also be explored in the future

Mental Models of Verifiability in Voting

In order for voters to verify their votes, they have to carry out additional steps besides selecting a candidate and submitting their vote. In previous work, voters have been found to be confused about the concept of and motivation for verifiability in electronic voting when confronted with it. In order to better communicate verifiability to voters, we identify mental models of verifiability in voting using a questionnaire distributed online in Germany. The identified mental models are Trusting No Knowledge Observer Personal Involvement and Matching models. Within the same survey, we identify terms that can be used in place of ‘verify’ as well as security-relevant metaphors known to the voters that can be used to communicate verifiability

Contextualized Security Interventions in Password Transmission Scenarios

Usable security user studies as well as the number of successful attacks to end users’ data and devices show that today’s security interventions like the green URL bar and self-signed certificate warnings do not protect end users effectively for many reasons. To improve the situation, we proposed the Framework fOr Contextualized security Interventions (FOCI). While this framework provides general guidelines how to develop contextualized security interventions, this is the first paper in which this framework is applied to actually develop adequate security intervention strategies and intervention content. We focus on a subset of security- and privacy-critical scenarios in the context of web applications – namely those in which users visit web pages containing a password filed. If either the communication is not confidential and authenticated or the service behind the web page is not trustworthy, entering a password can have consequences like financial loss and privacy leakage in particular for users reusing their passwords for several different web pages. Therefore, it is important to provide effective security interventions for these scenarios.&nbsp