Tobias Pulls

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Deep packet inspection technology became a cornerstone of Internet censorship by facilitating cheap and effective filtering of what censors consider undesired information. Moreover, filtering is not limited to simple pattern matching but makes use of sophisticated techniques such as active probing and protocol classification to block access to popular(More)
This paper discusses the approach taken within the PrimeLife project for providing userfriendly privacy policy interfaces for the PrimeLife Policy Language (PPL). We present the requirements, design process and usability testing of the “Send Data?” prototype, a browser extension designed and developed to deal with the powerful features provided by PPL. Our(More)
DIMACS/BIC/A4Cloud/CSA International Workshop on Trustworthiness, Accountability and Forensics in the Cloud (TAFC) 2013 Abstract. The goal of this work is to reason on the complexity of the relationship between three non-functional requirements in cloud computing; privacy, accountability, and transparency. We provide insights on the complexity of this(More)
We present a prototype of the user interface of a transparency tool that displays an overview of a user's data disclosures to different online service providers and allows them to access data collected about them stored at the services' sides. We explore one particular type of visualization method consisting of tracing lines that connect a user's disclosed(More)
Transparency is a basic privacy principle and factor of social trust. However, the processing of personal data along a cloud chain is often rather intransparent to the data subjects concerned. Transparency Enhancing Tools (TETs) can help users in deciding on, tracking and controlling their data in the cloud. However, TETs for enhancing privacy also have to(More)
The Data Track is a transparency-enhancing tool that aims to educate users by providing them with an overview of all their data disclosures. In this paper, we describe a cryptographic scheme for storing all data disclosures tracked by the Data Track centrally in the cloud in a privacy-friendly way. Our scheme allows users to store their data anonymously,(More)
Public cloud storage services are gaining in popularity and several commercial actors are offering their services for users, however, not always with the security and privacy of their users as the primary design goal. This paper investigates side channels in public cloud storage services that allow the service provider, and in some cases users of the same(More)
We present Balloon, a forward-secure append-only persistent authenticated data structure. Balloon is designed for an initially trusted author that generates events to be stored in a data structure (the Balloon) kept by an untrusted server, and clients that query this server for events intended for them based on keys and snapshots. The data structure is(More)