Capability-based security in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is capability-based security?

It is a security model where access to resources is controlled by unforgeable tokens called capabilities, which specify the rights a user or process has.

intermediate

How do capabilities differ from traditional access control lists (ACLs)?

Capabilities are tokens held by users or processes granting access, while ACLs list permissions attached to resources. Capabilities move with the user, ACLs stay with the resource.

intermediate

Why are capabilities considered unforgeable?

Because the system ensures capabilities cannot be copied or altered by unauthorized users, often by using protected memory or cryptographic methods.

beginner

Give a real-life example similar to capability-based security.

Like having a hotel room key card that only opens your room. The card (capability) grants you access without needing to check a list every time.

intermediate

What is a key benefit of capability-based security?

It simplifies access control by directly associating rights with tokens, reducing the risk of unauthorized access and making delegation easier.

What does a capability in capability-based security represent?

A A password for user login

B A list of users allowed to access a resource

C A token granting specific access rights

D A firewall rule

A capability is a token that grants specific access rights to a resource.

Which of the following is a key feature of capabilities?

A They can be easily forged by users

B They are unforgeable tokens

C They are stored only on the resource

D They list all users with access

Capabilities are designed to be unforgeable to ensure security.

In capability-based security, who holds the capability?

A The user or process needing access

B The system administrator only

C The resource owner only

D No one holds capabilities

Users or processes hold capabilities that grant them access.

How does capability-based security improve delegation?

A By disabling access sharing

B By requiring passwords for every access

C By listing all users in an ACL

D By allowing capabilities to be passed to others

Capabilities can be passed or delegated to others, making access control flexible.

Which analogy best describes capability-based security?

A A hotel room key card

B A public notice board

C A locked door with no key

D A guest list at a party

A hotel room key card is like a capability granting access to a specific room.

Explain what capability-based security is and how it controls access to resources.

Think about how a token or key can grant access without checking a list.

Describe the advantages of using capabilities over traditional access control lists.

Consider how capabilities make sharing and controlling access easier.