4f - Security of Distributed Databases

4f - Security of Distributed Databases

1. Interception of data

   • External communication links are the most vulnerable point for interception of data
   • Is a risk for:
     • Partitioned databases
     • Centralised databases with local index
   • Small risk for replicated databases when data is being updated
   • Encryption is solution

2. Physical access of data

   • Any sensitive data requires security
     • Physical
     • User-level
     • Anti-virus
     • Firewall
     • Anti-spyware
     • Encryption
   • Security only required at central location for centralised databases
   • All types of security are required at every site for partitioned and distributed databases

3. Centralised databases

   • All data is stored in one place
   • Updates only happen to one set of data
   • Integrity and consistency are maintained
   • Local Indexes
     • Require updates
     • Based on centrally stored data, so are straightforward

4. Vertically partitioned databases

   • Each field is only stored once, so updates only take place once
   • Integrity and consistency maintained
     • Except when the primary key changes, as it must be changed at all sites

5. Horizontally partitioned databases

   • Data is seperated by records, so each record is complete at the site it is stored at
   • Therefore, no issues with updating data

6. Replicated Databases

   • The whole database is replicated at each site
   • So lots of opportunity to compromise integrity