In a mobile ad-hoc network, nodes cannot rely on any fixed infrastructure for routing purposes. Rather, they have to cooperate to achieve this objective. However, the absence of any trusted third party in such networks may result in nodes deviating from the routing protocol for selfish or malicious reasons. The concept of trusted routing has been promoted to handle the problems selfish and mali...

One of the major security aspects in mobile communication networks concerns information about the localization of the (mobile) network user. This information may be protected by establishing a trusted third party that is responsible for creating suitable pseudonyms for the user identity. Distributing the maintenance of pseudonyms among n independent trusted parties allows to increase further th...

While anonymous payments are necessary for privacy reasons, they can as well be misused for criminal activities: Anonymous electronic cash can be used to conduct crimes that would be impossible with physical cash. As potential misuse of anonymity cannot be tolerated, the allowed anonymity has to be restricted. Payment systems with restricted anonymity are commonly based on the concept of a trus...

Over the past 20 years, websites have grown increasingly complex and interconnected. In 2016, only a negligible number of sites are dependency free, and over 90% of sites rely on external content. In this paper, we investigate the current state of web dependencies and explore two security challenges associated with the increasing reliance on external services: (1) the expanded attack surface as...

As a value-added service for standard email systems, a certified email scheme allows a sender to deliver a message to a receiver in a fair way in the sense that either the sender obtains a receipt from the receiver and the receiver accesses the content of the email simultaneously, or neither party gets the expected item. In this paper, we first point out some weaknesses in several existing sche...

Remote attestation (RA) is a popular means of detecting malware in embedded and IoT devices. RA is usually realized as an interactive protocol, whereby a trusted party – verifier – measures integrity of a potentially compromised remote device – prover. Early work focused on purely softwarebased and fully hardware-based techniques, neither of which is ideal for low-end devices. More recent resul...

The actual trend in the transport industry is to have electronic systems without mechanical back-up, so-called ”bywire” systems. Micro-computers control steering, brakes, power train etc... Robust protocols are needed to make these micro-computers communicate. They should be faulttolerant and yet not let the micro-computers split into disjoint communicating subsets. TTP is a time-triggered prot...