Token-Based Access Control (TBAC) is a security management mechanism that associates a list of objects and their related privileges with each user. In other words, each user is assigned a token that specifies which resources (objects) the user can access and which operations (privileges) they can perform on those resources.

Key Features of TBAC

1. Association of Objects with Tokens: In a TBAC system, objects (resources) and their related privileges are associated with user tokens rather than a central list. This means that each user has a personalized token that lists accessible resources and the associated permissions.
2. Privilege Management: Privileges are specified within the token. These privileges can include operations such as reading, writing, modifying, or deleting an object. The system verifies the user’s token to determine if the requested action is permitted.
3. Security and Scalability: TBAC is considered secure and scalable. It is secure because it reduces the risk of unauthorized access by centralizing control within user tokens. It is scalable because it can easily handle a large number of users and resources without the need to maintain a central access list.
4. Authentication and Authorization: A TBAC system relies on two crucial phases: authentication and authorization. During authentication, the user provides credentials to prove their identity. Once authenticated, the system checks the user’s token to authorize access to the requested resources.

Advantages of TBAC

• Decentralization of Control: Since tokens contain all the necessary information about user privileges, there is no need for a central list, thereby reducing bottlenecks and improving system efficiency.
• Flexibility: Tokens can be easily updated or revoked, allowing for dynamic management of user privileges.
• Reduction of Administrative Burden: Token management can be automated, reducing the workload for system administrators.

Differences from List-Based Access Control

Unlike TBAC, List-Based Access Control (LBAC) maintains a central list that associates users with resources and their related privileges. This list must be consulted every time a user attempts to access a resource, which can introduce inefficiencies and difficulties in centralized privilege management.

In summary, Token-Based Access Control represents a flexible and secure approach to managing user permissions, adapting well to scenarios with a large number of resources and users, where scalability and decentralization of control are essential.