needs to be revoked prematurely. For this reason, whenever a client (user or program) needs to assert the validity of another party's certificate, it performs revocation checking. There are many revocation techniques varying in both the operational model and underlying data structures. One

of privacy in revocation checking and its contribution is two-fold: it identifies and explores the loss of privacy inherent in current revocation checking, and, it constructs a simple, efficient and flexible privacy-preserving component for one well-known revocation method. 1

of privacy in revocation checking and its contribution is two-fold: it identifies and explores the loss of privacy inherent in current revocation checking, and, it constructs a simple, efficient and flexible privacy-preserving component for one well-known revocation method. 1

1.1 Private and Public Key Cryptography..................... 5

necessarily representing the official policies or endorsements, either express or implied, of ARO,

Hiermit versichere ich, die vorliegende Diplomarbeit selbstständig und unter ausschliesslicher Verwendung der angegebenen Quellen und Hilfsmittel angefertigt zu haben. Diese Arbeit hat in gleicher oder ähnlicher Form noch keiner Prüfungsbehörde vorgelegen. Darmstadt, 14. Februar 2006

, the goal is to develop a universally accepted formal framework for describing complex and flexible interacting Web applications featuring notably data exchange, sharing, integration, querying, and updating. We also propose to develop formal foundations that will enable peers to concurrently reason about

to extend the short signature scheme to give simple ring signatures Ensuring Data storage Security in cloud Computing(2009) To ensure the correctness of user's data in cloud data storage,a effective and flexible distributed scheme with explicit dynamic data support is proposed by C. Wang, Q. Wang, K

trends take us in a direction so far away from selflessly safeguarding public interest that the idea has become untenable, or outdated? • The public service must be flexible and at the same time provide long-term stability. This requires continuously learning and adapting, which indicates that more needs

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Movement of wireless sensor and actuator networks, and of nodes between WSANs are becoming more commonplace. However, enabling remote usage of sensory data in multiple applications, remote configuration, and actuation is still a big challenge. The purpose of this paper is to analyse and describe which mobility support can best be used in different scenarios, and how shared usage of mobile WSANs by multiple IP applications can best be scaled up. This paper describes logistic and person monitoring scenarios, where different types of movements take place. These mobility types and their implications are categorized and analysed. Different degrees of support for these mobility types are analysed in the context of the mobility scenarios. Additionally, different schemes are analysed for shared use of mobile WSANs by multiple applications. In conclusion, guidelines are provided for dealing with mobile and overlapping WSANs and the most promising scheme for shared use of mobile WSANs by IP applications. 1.