In this paper, we present MiniWorld, a novel distributed network emulator. It is based on full virtualization using QEMU/KVM, offers three network backends for emulating both wired and wireless communication, and provides several mobility patterns as well as distance-based link quality models. A snapshot boot mode is offered for accelerated booting of identical environments and repeating emulation runs. To decrease runtimes, MiniWorld supports distributed emulation across multiple computers, based on a resource-aware virtual machine (VM) scheduler. Experimental results demonstrate the performance of MiniWorld with respect to VM boot times, network bandwidth, round trip times, and topology switching times.

Serval is an open-source, delay-tolerant wireless ad-hoc networking system designed to allow communications anywhere and anytime, despite the total loss of supporting telecommunications infrastructures provided by mobile phone operators. In emergency situations, Serval can be used to establish a disaster-response communications network spontaneously formed by mobile phones and/or battery powered wireless routers. In this paper, we present an in-depth experimental evaluation of Serval for various network setups and usage patterns, including simulated long term use. The focus of our evaluation is on the delay-tolerant aspects of Serval, providing insights into the scenarios where Serval can be deployed with satisfactory quality and performance characteristics. Furthermore, since mobile phones have a limited battery capacity, we take a closer look at the battery drain resulting from using Serval over different communication links, such as WiFi and Bluetooth. Our purpose in providing these analyses is to understand the current capability of Serval and identify any areas where further improvement is required, and to provide a summary of current readiness of Serval in advance of planned pilots in the Pacific region.

The mobile device sector has grown over the past years. Most of us have a smartphone or tablet carrying with us every day. But the advanced mobility also requires special security enforcement as the devices store a lot of sensitive data and can be easily stolen or lost. Developers for the iOS platform have to pay attention to avoid common pitfalls when developing applications. Buffer overflows, format string vulnerabilities, SQL injections, Cross-Site Scripting, data leakage or theft are security issues which can happen if user input has not been sanitized correctly. This paper is meant to point out common mistakes in the iOS app development by showing Objective-C and Swift source code. Furthermore, it introduces the reader to the principles of reverse engineering so that third party applications can be audited for those bug classes.

In recent years, the number of mobile applications has grown significantly. Not surprisingly, various security and privacy concerns associated with mobile applications have emerged. Several researchers are addressing these problems by analyzing the security properties of mobile application code. Most of the security checks rely on custom scripts and are quite heterogeneous with respect to dependencies, deployment and reporting. In this paper, we present AndroLyze, a distributed framework with unified logging and reporting functionality to perform security checks on large numbers of applications in an efficient manner. AndroLyze provides optimized scheduling algorithms for distributing static code analysis tasks across several machines. Moreover, AndroLyze can handle several versions of a single mobile application to generate a security track record over many versions. To demonstrate the benefits of AndroLyze, we have analyzed the Top Free 500 Android applications of all categories in Google Play collected over three years. The resulting data set consists of almost 40,000 mobile applications and requires about 227 GB of storage space.

Zusammenfassung—Das Internet hat in den vergangenen Jahren immer mehr an Bedeutung erlangt. Jedoch ist man im Internet nicht anonym, denn jeder Nutzer ist durch seine IPAdresse identifizierbar. Des Weiteren ist die Tatsache, dass zwei Parteien miteinander kommunizieren auch kein Geheimnis. Außerdem ist es nicht für jeden frei zugänglich, weil zensierende Staaten wie China Teile des Internet blockieren. Für diese Zwecke u.a. existieren Systeme mit denen sowohl Zensur umgangen werden kann als auch anonyme Kommunikation ermöglicht wird. Mit Hilfe solcher Darknets kann die Identität, je nach System, entweder im regulären Internet oder in einem in sich geschlossen Netzwerk, verschleiert werden. Meist wird dafür eine Kaskade von Knoten aufgebaut, über die die Kommunikation dann stattfindet. Der letzte Knoten nimmt dann Kontakt mit dem Ziel auf. Dabei kennt jeder Knoten nur seinen vorhergehenden und nachfolgenden Knoten. Das Ziel dieser Ausarbeitung ist die Darknets Freenet, Tor und I2P vorzustellen. Auf die Sicherheit sowie mögliche Angriffsszenarien, die die Schwachstellen des jeweiligen Darknet ausnutzen, um die Identität eines Nutzers aufzudecken, wird nicht eingegangen.

In this article, we examine the technology acceptance of cloud computing by analyzing empirical data from 100 CIOs and IT managers from stock indexed companies using factor analysis. For a valid methodological background we use a modified version of the common Technology Acceptance Model. The outcomes indicate that user acceptance of cloud computing can be explained and predicted by various non monetary variables concerning social influence and cognitive instrumental process. In particular, factors such as image, job relevance and perceived usefulness play an important role in cloud computing acceptance. These findings advance theory and contribute to the foundation for future research aimed at improving our understanding of technology adoption behavior. They also provide a structured and more systematic approach for cloud service providers on how to build their services and promoting them to the market.

The environmental impact of IT is facing increasing public attention. The search engine Ecosia takes advantage of this situation by pursuing a Social Business model. Search engines need electricity to provide their services and indirectly produce CO2. The estimation of greenhouse gas emissions for the average search query using the market leader Google fluctuate between 0.2 g and 10.0 g of CO2. The search engine Ecosia tries to compensate the emissions by donating most of its revenues to the World Wildlife Fund (WWF) and save rainforest from deforestation. Rainforests process CO2 through photosynthesis and store it as carbon. The question arises if Social Business models in general possess potential for success in the search engine market. To investigate this question we apply case study research. Additionally, we use a survey to evaluate what is important to users and which aspects of search engines influence the customer’s attitude towards social business.