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XML is a widely used standard for information storage and exchange in today's IT systems. Therefore, it is essential to protect XML documents from unauthorized access. For this purpose, we present a model for access control for XML documents with three key features. First, we record the effects of the operations on the documents in a history, depending on which we can grant or deny access. Second, we use the history information to define permissions for the operations of our model including the transfer of document parts. Third, since the text content of an element can be composed of parts of text from different sources, we consider units smaller than the XML element as a protection unit. Therefore, we keep track of these parts and allow to define access to them individually.

With the emergence of business to business eCommerce conventional trading practices need to be adapted to the new electronic environment. One such trading practice is the call for tender (CFT) which is heavily used for trading perishable goods. A naive translation of the CFT to mediated eCommerce introduces new manipulation possibilities like identity masquerading, repudiation of messages etc. In a first step. we show how the basic CFT can be made robust against these security attacks. However. this approach does not eliminate fundamental economic design problems of the CFT itself. In a second step. we show how the CFT can be protected against attacks that damage the fairness and economic efficiency of a market by turning it into a secure sealed-bid auction protocol.

This paper presents a methodology for assessing and improving the quality of information provided by corporate wikis. Regarding the assessment, we present two KPIs for measuring relative demand and relative usefulness of wiki articles, including corresponding processes and data model. In regard to improving quality, we use the KPIs to classify the articles. For this classification, we introduce four categories and discuss possible actions for reducing information overload and increasing the visibility of articles. To prove our methodology, we analyze an existing corporate wiki of a large European enterprise in the chemical industry. Its articles are used to demonstrate how the proposed KPIs can contribute to knowledge management by improving the information quality.

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