Date Added: Dec 2011
With rise in reliance on distributed information systems for daily business, all business organization are now vulnerable to security threats. A number of techniques are currently available to protect data when transmitted across sites. The data protection must also include mechanisms for enforcing access control policies based on data contents, subject qualifications and characteristics, and other relevant contextual information, such as time. The semantics of data must be taken into account in order to specify effective access control policies. The integrity and availability specifically tailored to database systems must be adopted.