What is RBAC vs ABAC vs PBAC?

5 min read

Setting employee controls for IT to manage is the biggest challenge to cloud-native expansion, according to 64% of the developers surveyed in our 2022 Cloud-Native Alignment report. 

To help you choose the best access control model for your organization or application, we compare the most popular options: 

  • Role-Based Access Control (RBAC)
  • Attribute-Based Access Control (ABAC)
  • Policy-Based Access Control (PBAC) 

Understanding the differences between RBAC vs ABAC vs PBAC is critical for choosing an appropriate access control method for your organization or application. 

With the right solution, you can ensure your data is protected while keeping implementation and maintenance costs low. These frameworks are all designed to facilitate authorization and limit access to digital resources, but their functioning considerably impacts enterprise cybersecurity and related expenditures.

Role-based access control (RBAC)

The traditional model to assess authorization requests is Role-Based Access Control. RBAC depends on pre-defined roles, each with a unique set of permissions. Any employee designated to a particular role will have the same level of access to resources as any other person who shares that designation. 

RBAC is an example of coarse-grained authorization. Specific attributes of the authorization request, such as time and location, cannot be taken into account with an RBAC framework. You must define a new role for an employee if even a single permission granted to their previous role needs to be modified. Additionally, RBAC introduces scalability issues as new roles and positions are added to the company structure.

Check out our whitepaper for more information about RBAC limitations

Attribute-based access control (ABAC)

Attribute-based access control, as the name implies, relies on specific attributes of the authorization request, instead of being bound by a predefined role. This capability means that you can map any central security policy onto a set of attributes that determine whether or not access to a specific resource is granted. 

Examples of parameters in ABAC include:

— User ID/role/department

— The time, location and device information

— The name, creator and file type of the resource in question

In moving away from RBAC, ABAC provides much greater flexibility in terms of who gets access to which resource in an enterprise, regardless of their designation. It also allows for the time and location of the request to be considered, making it possible to provide area-specific and time-bound access, when needed.

The use of attributes instead of roles allows for more granularity with a highly customizable set of permissions for each member of the enterprise, making ABAC a fine-grained access control method. IT staff can also set new attributes to account for the diversification of the workforce as the enterprise scales up.

With centralized data storage, cloud computing requires more granularity in access controls to be secure. According to a 2022 report by Flexera, 89% of respondents already had a multi-cloud strategy. As enterprises shift to cloud workloads, the use of fine-grained authorization methods, such as ABAC, will continue to grow. 

Policy-based access control (PBAC)

Like ABAC, policy-based access control (PBAC) uses a combination of attributes to determine whether or not to authorize an access request. The parameters included are just as comprehensive as those of ABAC. 

The management of policy-based access control is an already established market that is seeing rapid growth, according to a report by KuppingerCole. Policies allow the system to evaluate requests in varying contexts and according to real-time values of attributes. 

ABAC relies on company policies being mapped onto a predefined list of attributes that it then considers for authorization. In contrast, PBAC relies on a set of predefined company policies, written in code, to determine the values of each attribute in a valid request. 

PBAC uses logic to determine how specific policies are to interact with each other. Additionally, separating policy logic from the software code allows for policy changes without impacting the business functions of applications or resources. 

ABAC vs RBAC vs PBAC: Which model should you adopt?

After understanding how these authorization models function, it’s useful to spell out what the differences in each framework mean for an enterprise looking to improve its access control mechanisms. 

The table below illustrates key differences in functionality for each model:

Permissions depend onPredefined roles with the same set of permissions across each role.Sets of specific attributes for each request to determine relevant permissions.Sets of specific policies that determine relevant attributes and permissions.
Type of access controlCoarse-grainedFine-grainedFine-grained
Real-time parametersNoYesYes
Context specificityNew roles can be defined for each new context of permissions needed.Sets of attributes can be defined for each new context of permissions needed.Policies can be defined to adjust the attributes for each new context.
Cost to implement and maintainRelatively cheap because it can be maintained by a small IT department.Costly because it requires a large experienced IT team to maintain.Implementation is costly, but maintenance is not.
Ease of complianceAssignment of a role may give certain employees unwanted access to sensitive information. Compliance is difficult to ensure.Highly-specific permissions can be granted, but the translation of company policies from the business to the IT end can cause errors and weaken compliance.Easy-to-use GUI and reliance on policies allow business managers to set permissions directly, ensuring high compliance.
Ease of modificationFairly easy to define new roles or revoke certain permissions for a particular role, but the risk of role explosion is high.Difficult to define new attributes. It may require coding knowledge.Relatively easier to define new policies using high-level policy language. 

The choice of model depends on the enterprise’s current needs and future aspirations. However, the limitations of RBAC are significant in terms of scalability and diversification. ABAC provides a great alternative, but implementation can be complex. The complexity can create a large gap between those making the policies at the business end and those implementing them in the IT department. 

Simplify access control with OPA and Styra DAS

Open Policy Agent (OPA) is an open-source policy engine that uses policy-as-code to externalize authorization decision-making. As a policy lifecycle management platform for OPA, Styra Declarative Authorization Service (DAS) offers a way toward a unified authorization through policy-based access control and an intuitive GUI. 

Free from the compliance risks of RBAC and the complexity of ABAC, Styra DAS creates a bridge between the policy formulation and implementation processes to facilitate highly contextualized compliance.

And there’s no need to choose between coarse and fine-grained authorization. With Styra DAS and policy as code, you can implement either RBAC or ABAC or a combination of the two according to your organization’s needs.

The policy impact analysis and compliance monitoring features allow developers to catch errors in access control early on and rectify them collaboratively with the authors of new policies. Styra DAS makes it easy to maintain the level of security and compliance needed for any growing enterprise. 

RBAC vs ABAC vs PBAC — use any of these methods with Styra DAS. Book a Styra DAS demo today and get your authorization solution up and running within minutes.  


Is PBAC the same as ABAC?

Policy-based access control (PBAC) and attribute-based access control (ABAC) are both frameworks that use attributes to make authorization decisions. However, with PBAC, you can write policies in a high-level policy language that shows the authorization engine what to do in a certain situation. With ABAC, you generally need to tell the authorization engine how to do it as well. 

What are the three rules of RBAC?

The three rules of RBAC are: 

1. Role assignments: Users are assigned a role. 

2. Role authorization: Users’ roles must be authorized. Users cannot assign roles to themselves.

3. Permission authorization: Users can only use permissions assigned to their roles.

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