Journal:Informatica
Volume 26, Issue 2 (2015), pp. 181–198
Abstract
Abstract
This paper proposes an access control mechanism of verifiable cloud computing services using chameleon hashing and Diffie–Hellman key exchange protocol. By this mechanism, an entity can apply for cloud computing services and he can authorize other users to access granted data or services. When an authorized user or entity wants to access cloud computing services, he can authenticate the cloud computing service provider. Moreover, no entity secret will be revealed by data kept by cloud servers such that security and cost saving can be both ensured. Security proof under the simulation paradigm is also given.
Journal:Informatica
Volume 8, Issue 1 (1997), pp. 23–42
Abstract
Today's multimedia and hypermedia systems include such a huge amount of data and links, that they should be stored and maintained by a database system. Then a powerful and efficient database schema is needed. The Dexter hypertext reference model offers a widely accepted, powerful modelling technique for nodes and links. We present its stepwise conversion into a relational multimedia database schema. In the obtained hypermedia engine the most important and most time critical operation is the link navigation. We analyze its complexity in detail and optimize it by schema improvements. Finally we present an efficient implementation of the presented ideas: the System MultiMAP, developed at the TU Munich.