Cloud computing allows developers of mobile apps to overcome limited computing, storage, and power resources of modern smartphones. Besides these huge advantages, the hidden utilization of cloud services by mobile apps leads to severe privacy concerns. To overcome these concerns and allow users and companies to properly assess the risks of hidden cloud usage, it is necessary to provide transparency over the cloud services utilized by smartphone apps. In this paper, we present our ongoing work on TRINICS to provide transparent information on individual cloud service usage. To this end, we analyze network traffic of smartphone apps with the goal to detect and uncover cloud usage. We present the resulting statistics on cloud usage to the user and put these numbers into context through anonymous comparison with users' peer groups (i.e., users with similar sociodemographic background and interests). By doing so, we enable users to make an informed decision on suitable means for sufficient self data protection for their future use of apps and cloud services.

Virtual data centers allow the hosting of virtualized infrastructures (networks, storage, machines) that belong to several customers on the same physical infrastructure. Virtualization theoretically provides the capability for sharing the infrastructure among different customers. In reality, however, this is rarely (if ever) done because of security concerns. A major challenge in allaying such concerns is the enforcement of appropriate customer isolation as specified by high-level security policies. At the core of this challenge is the correct configuration of all shared resources on multiple machines to achieve this overall security objective. To address this challenge, this paper presents a security architecture for virtual data centers based on virtualization and Trusted Computing technologies. Our architecture aims at automating the instantiation of a virtual infrastructure while automatically deploying the corresponding security mechanisms. This deployment is driven by a global isolation policy, and thus guarantees overall customer isolation across all resources. We have implemented a prototype of the architecture based on the Xen hypervisor.

Identity theft through phishing attacks has become a major concern for Internet users. Typically, phishing attacks aim at luring the user to a faked Web site to disclose personal information. Existing solutions proposed against this kind of attack can, however, hardly counter the new generation of sophisticated malware phishing attacks, e.g., pharming Trojans, designed to target certain services. This paper aims at making the first steps towards the design and implementation of a security architecture that prevents both classical and malware phishing attacks. Our approach is based on the ideas of compartmentalization for isolating applications of different trust level, and a trusted wallet for storing credentials and authenticating sensitive services. Once the wallet has been setup in an initial step, our solution requires no special care from users for identifying the right Web sites while the disclosure of credentials is strictly controlled. Moreover, a prototype of the basic platform exists and we briefly describe its implementation

Over the past years, the computing industry has started various initiatives announced to increase computer security by means of new hardware architectures. The most notable effort is the Trusted Computing Group (TCG) and the Next-Generation Secure Computing Base (NGSCB). This technology offers useful new functionalities as the possibility to verify the integrity of a platform (attestation) or binding quantities on a specific platform (sealing).In this paper, we point out the deficiencies of the attestation and sealing functionalities proposed by the existing specification of the TCG: we show that these mechanisms can be misused to discriminate certain platforms, i.e., their operating systems and consequently the corresponding vendors. A particular problem in this context is that of managing the multitude of possible configurations. Moreover, we highlight other shortcomings related to the attestation, namely system updates and backup. Clearly, the consequences caused by these problems lead to an unsatisfactory situation both for the private and business branch, and to an unbalanced market when such platforms are in wide use.To overcome these problems generally, we propose a completely new approach: the attestation of a platform should not depend on the specific software or/and hardware (configuration) as it is today's practice but only on the "properties" that the platform offers. Thus, a property-based attestation should only verify whether these properties are sufficient to fulfill certain (security) requirements of the party who asks for attestation. We propose and discuss a variety of solutions based on the existing Trusted Computing (TC) functionality. We also demonstrate, how a property-based attestation protocol can be realized based on the existing TC hardware such as a Trusted Platform Module (TPM).

Many applications of cryptographic identification protocols are vulnerable against physical adversaries who perform real time attacks. For instance, when identifying a physical object like an automated teller machine, common identification schemes can be bypassed by faithfully relaying all messages between the communicating participants. This attack is known as mafia fraud.The Probabilistic Channel Hopping (PCH) system we introduce in this paper, solves this problem by hiding the conversation channel between the participants. The security of our approach is based on the assumption that an adversary cannot efficiently relay all possible communication channels of the PCH system in parallel.