Capability

Why
Capabilities are important because it is a lower level interface that we use to implement access control matrix

What
These are basically the opposite of ACL in terms of costs and benefits.

Windows
The most important implementation of capabilities is on the Windows OS. There are two important changes that Windows 2000 brought to the ACL implementation of Windows NT:
 * 1) Users/Groups can be blacklisted/whitelisted based on their profiles
 * 2) Elevation prompt is used. When a user logs in, they get two tokens. One default token and one admin token. This means that they browse as a normal user and malware can't take control of system resources with admin level access. When a program wants to be run, then we enter an admin password to run it with admin priveleges.