What is Capability-based addressing?

In computer science, capability-based addressing is a scheme used by some computers to control access to memory as an efficient implementation of capability-based security. Under a capability-based addressing scheme, pointers are replaced by protected objects that can be created only through the use of privileged instructions which may be executed only by either the kernel or some other privileged process authorised to do so. This effectively allows the kernel to control which processes may access which objects in memory without the need to use separate address spaces and therefore requiring a context switch when an access occurs.