Communications and data security in distributed information systems
Agnieszka Dardzińska · 2006
Abstract: Distributed Information Systems can be described as a collec-tion of autonomous information systems which can communicate with each other.This communication can be driven by request for knowledge needed to predict for maximal optimization what values should replace null values in in-complete or missing attributes. Any incompleteness in data can be seen as the result of partial knowledge about properties of objects stored in distributed in-formation system but also some attributes might be just hidden because of the security reason. In such case we have to be certain that the missing data can not be reconstructed from the available data by any known null value impu-tation method and that some informations in information system can not be uncovered. Let us assume that an attribute h is hidden at one of the sites of distributed information system, denoted by S and called a client. Trying to reconstruct this attribute, a request for a definition of this attribute can be sent by S to some of the remote sites. These definitions can be used by Chase algo-rithm to impute missing values for objects at S. In this paper we show how to identify these objects in S and how to optimize the system. We also show which values have to be hidden from users to guarantee that the hidden attribute in S can not be reconstructed in any way.