To consider the controls or countermeasures that attempts to prevent exploiting computing system vulnerabilities, we begin by thinking about traditional ways to enhance physical security. In the middle ages, castles and fortresses were built to protect the valuable people and property inside. The fortress might have had one or more security characteristics including-
- A strong gate or door to repel invaders
- Heavy walls to withstand objects thrown or projected against them
- A surrounding moat, to control access
- Arrow slits to let archers shoot at approaching enemies
