System security management
We have seen how the separation of privilege levels between kernel and user modes supports the effective separation of applications started by one user from those of other users and from system processes. This represents security at the level of executing software.
This is fine as far as it goes, but what about systems that must remain secure even when untrusted users have unrestricted physical access to them? Additional measures must be implemented at the hardware level to prevent curious or malicious users from accessing protected code, data, and hardware resources.
Before getting into the details of hardware-level security features, it is helpful to list some of the categories of information and other resources that must be protected in digital systems:
- Personal information: Information such as government identification numbers, passwords for accessing bank accounts, contact lists, emails, and text messages must be protected even if...
