When it comes to user authorization, there isn’t a one-size-fits-all solution. Depending on your specific needs, Policy-Based Access Control (PBAC) and Zanzibar-based authorization each offer unique benefits. However, for many scenarios, PBAC, especially when implemented with a stateless architecture like Cerbos, stands out as a highly versatile and efficient option. Let’s explore the differences between these two approaches and help you determine which one is right for your application.

What Makes PBAC so Effective?

Policy-Based Access Control, or PBAC, makes access control decisions based on a set of defined policies. Imagine having a flexible rulebook that your application consults every time someone tries to access something. This adaptability is one of the main reasons why PBAC is widely adopted across different industries and applications.

PBAC supports various access control models, including

• Attribute-Based Access Control (ABAC): Uses attributes of users, resources, and the environment to make access decisions.
• Role-Based Access Control (RBAC): Grants access based on user roles.
• Relationship-Based Access Control (ReBAC): Determines access based on relationships between users and resources.

With PBAC, policies are evaluated in real time, ensuring that your app always works with the most current information. This real-time evaluation is crucial for applications that need to respond quickly to changes in user roles or data, making PBAC a versatile solution for many use cases.

Advantages of PBAC

• Real-Time Decision Making: Ensures access decisions are based on up-to-date data, reducing the risk of unauthorized access.
• Flexibility: Adapts to various access control models and can handle complex scenarios.
• Ease of Management: Policies are written in a straightforward, human-readable format, making them easy to create, test, and modify.

Why Cerbos’s Stateless Approach Enhances PBAC

• Scalability and Performance: Cerbos’s stateless architecture allows for horizontal scaling without the overhead of maintaining state. This enables handling a large number of authorization requests quickly and efficiently.
• Simplicity in Deployment: Stateless systems are easier to deploy and manage because they don’t require complex state synchronization across different servers. This makes your authorization infrastructure more resilient and easier to maintain.
• Reduced Latency: Without the need to manage state, Cerbos reduces latency in processing authorization requests, making it ideal for applications that demand high performance and low response times.

To learn more about how PBAC and Cerbos’s stateless architecture can optimize your authorization processes, check out how Cerbos implements PBAC.

Where Zanzibar-Based Authorization Fits Best

Zanzibar-based authorization is another robust method, inspired by Google’s approach to access control for its services like Google Docs and YouTube. Zanzibar uses a centralized system to manage access control lists (ACLs) for each resource, providing fine-grained control over who can access what.

Zanzibar is especially effective for applications with vast numbers of individual resources, each with unique permissions. It’s designed for environments where precise control over each resource is necessary, and it ensures consistency by centralizing all access control logic in one place.

Benefits of Zanzibar-Based Authorization:

• Fine-grained control: Ideal for managing access to a large number of distinct resources with specific, individualized permissions.
• Centralized Management: Provides a single point of control, which can simplify auditing and policy enforcement for large-scale applications.

However, Zanzibar’s centralized nature requires constant synchronization between your application and the authorization system, which can introduce complexity and latency. This approach might be less suitable for applications that need to adapt quickly to changing data and user roles.

PBAC vs. Zanzibar: Choosing the Right Approach

Choosing between PBAC and Zanzibar depends on your application’s specific needs and constraints. Here’s a balanced look at what each approach offers:

When to Choose PBAC (with Cerbos) Over Zanzibar

If your application deals with dynamic data, frequently changing access requirements, or simply needs a flexible, easy-to-manage solution, PBAC with Cerbos is likely your best bet. It offers adaptability, real-time responsiveness, and the added benefits of Cerbos’s stateless architecture, making it ideal for most modern applications without synchronizing the application state or replicating database records to your authorization layer.

However, if your application manages a static collection of resources with highly specific access controls, Zanzibar could be a strong candidate. Its centralized approach ensures consistent and precise control, which can be advantageous in certain contexts.

Still not sure which approach is right for you? Learn more about how Cerbos can help you implement the best authorization strategy by booking some time to chat with an engineer.

Wrapping Up

Authorization doesn’t have to be complicated, but choosing the right approach can make all the difference. For most applications, PBAC, especially when implemented with a stateless architecture like Cerbos, offers an excellent balance of flexibility, simplicity, and performance. It’s designed to handle a variety of access control needs, making it the ideal choice for many modern, dynamic apps.

Remember, authorization is not a one-time setup – it's an ongoing process that requires continuous attention and refinement. So choose wisely, but also be prepared to adapt as your application evolves.