Florian Kelbert

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Distributed data usage control enables data owners to constrain how their data is used by remote entities. However, many data usage policies refer to events happening within several distributed systems, e.g. “at each point in time at most two clerks might have a local copy of this contract”, or “a contract must be approved by at least two clerks before it(More)
Usage control is concerned with how data is used after access has been granted. Enforcement mechanisms have been implemented for distributed systems like web based social networks (WBSN) at various levels of abstraction. We extend data usage control to heterogeneous distributed systems by implementing a policy enforcement mechanism for a smart meter(More)
Distributed usage control is concerned with how data may or may not be used after initial access to it has been granted and is therefore particularly important in distributed system environments. We present an application- and application-protocol-independent infrastructure that allows for the enforcement of usage control policies in a distributed(More)
Today’s electricity grid is evolving into the smart grid which ought to be reliable, flexible, efficient, and sustainable. To fulfill these requirements, the smart grid draws on a plenty of core technologies. Advanced Metering Infrastructure (AMI). These technologies facilitate easy and fast accumulation of different data, e.g. fine-grained meter readings.(More)
Usage control (UC) is concerned with how data may or may not be used after initial access has been granted. UC requirements are expressed in terms of data (e.g. a picture, a song) which exist within a system in forms of different technical representations (containers, e.g. files, memory locations, windows). A model combining UC enforcement with data flow(More)
Trusted execution support in modern CPUs, as offered by Intel SGX enclaves, can protect applications in untrusted environments. While prior work has shown that legacy applications can run in their entirety inside enclaves, this results in a large trusted computing base (TCB). Instead, we explore an approach in which we partition an application and use an(More)
Accountability aims to provide explanations for why unwanted situations occurred, thus providing means to assign responsibility and liability. As such, accountability has slightly different meanings across the sciences. In computer science, our focus is on providing explanations for technical systems, in particular if they interact with their physical(More)
Despite the increasing adoption of cloud-based services, concerns regarding the proper future usage and storage of data given to such services remain: Once sensitive data has been released to a cloud service, users often do not know which other organizations or services get access and may store, use or redistribute their data. The research field of usage(More)