Which of the following provides a specification for access rights and privileges in a system?

The correct choice is JSON Web Token (JWT). JWT is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT can be verified and trusted because it is digitally signed. This signature ensures the integrity of the claims and allows the system to specify access rights and privileges for users or entities based on the information within the token.

In systems where authentication and authorization are crucial, JWTs can help convey who the user is and what they are allowed to do, effectively providing the necessary specification for access rights and privileges. This capability makes it particularly useful in web applications where verifying user identity and managing access is vital.

Other options, while related to security and access control, serve different purposes. Lightweight EAP (LEAP) is primarily a security protocol used in wireless networks for authentication. Security Assertion Markup Language (SAML) is employed for exchanging authentication and authorization data between parties but focuses more on the assertion of those claims rather than directly defining access rights in the token. OpenID is used for decentralized authentication, allowing users to log in to multiple services with a single identity, but it does not inherently provide a specification for access rights and privileges within the tokens it uses.