The differences between authentication and authorization in software development

Published by Alex Olivier on September 25, 2023
The differences between authentication and authorization in software development

Authentication and authorization are two critical processes in software development that can help you ensure the security and integrity of your data and systems. The two terms are often used interchangeably, but they are actually two distinct processes that serve different purposes.

This article provides an overview of the differences between authentication and authorization in software development. You will learn what authentication and authorization mean and the different methods of implementing them and explore some examples of how they are used in different scenarios.


Authentication is the process of verifying the identity of a user or device. It typically involves presenting a set of credentials that are unique to the user or device, such as a username and password or a digital certificate. Overall, authentication is a critical first step to ensure that only authorized users or devices are granted access to your system or application. Without proper authentication measures, unauthorized users or devices can gain access to sensitive data and compromise the security of your system.

Your choice of authentication method depends on the level of security you require, the sensitivity of the data being accessed, and the user or device being authenticated. Some common authentication methods include passwords, biometric authentication, token-based authentication, two-factor authentication, multifactor authentication, and certificate-based authentication.

Password-based authentication

Passwords are one of the most commonly used authentication methods. In this method, your software system identifies users or devices based on a unique combination of letters, numbers, and symbols provided by the user or device. Password-based authentication is an effective choice if you are looking for an authentication method that is generally easy to use, has low implementation costs, and offers flexibility to users who need to change their credentials frequently. However, passwords are vulnerable to brute-force attacks, where an attacker attempts to guess the user’s password by trying different combinations of characters. Brute-force attacks are especially dangerous when users choose weak passwords that are easy to guess. Passwords are also particularly susceptible to social engineering, especially phishing attacks.

Biometric authentication

Biometric authentication uses unique physical characteristics such as fingerprints, facial recognition, and voice recognition to verify the identity of a user. Relative to passwords, biometric authentication provides a higher level of security because it uses physical characteristics that are difficult to replicate. Furthermore, biometric authentication is convenient for users because they don’t have to remember passwords in order to verify their identity. Although biometric authentication has several advantages, it can also be expensive to implement because it requires specialized hardware or software such as fingerprint scanners and cameras. Moreover, biometric authentication may not be accessible to users with disabilities or medical conditions that affect their physical characteristics.

Token-based authentication

You can also use a physical or digital token to verify a user’s identity. Physical tokens can take many different forms, such as key fobs, smart cards, or USB drives. Digital tokens include time-based one-time passwords (TOTP), JSON Web Tokens (JWT), or OAuth access tokens. In this authentication method, users must provide their physical or digital token to the system performing the authentication process to prove that they are who they claim to be. Token-based authentication is a highly secure and flexible authentication method, but it often constitutes a single point of failure due to dependence on the availability and proper functioning of specialized hardware.

Two-factor authentication

Two-factor authentication involves combining two separate methods of authentication, such as a password and a security token, to verify the identity of a user with an additional layer of security. For example, in addition to providing their regular passwords, users could also receive a digital token for one-time use via text message or email and provide the received token to verify that they are who they claim to be. Alternatively, after providing their regular passwords, a user could insert a specially configured USB drive into the computer performing the authentication process to provide further proof of identity. By combining two authentication methods, you can reduce the likelihood that a malicious user will gain access to your system by compromising the credentials for a single authentication method.

Multifactor authentication

Multifactor authentication goes a step beyond two-factor authentication and uses three or more methods of authentication to verify a user’s identity. While multifactor authentication offers a higher level of security than other types of authentication, it is generally more complex to implement and inconvenient for users relative to other approaches.

Certificate-based authentication

Finally, certificate-based authentication uses digital certificates to verify the identity of a user or device. A digital certificate is typically issued by a trusted third-party and contains information such as the user’s name, organization, and public key. You can use digital certificates in a wide variety of applications and systems. For example, you can use digital certificates in web applications to provide secure communication between the user’s browser and a web server. When a user visits a secure website, their browser will check for the website’s digital certificate and verify that it is valid and issued by a trusted Certificate Authority (CA). This verification process ensures that the user is communicating with the authentic website. Some examples of CAs include IdenTrustDigiCert, and Let’s Encrypt.

Certificates offer a high level of security, but they can be more complex to implement and manage relative to other types of authentication because they require specialized knowledge or expertise *and* dependence on a third-party to issue the digital certificates.


Authorization is the process of granting or denying access to certain resources or functionality based on a user’s identity and permissions. It allows you to control which users have access to specific data or functionality, even after they have been authenticated.

Proper authorization helps you maintain compliance with regulatory requirements and reduce the risk of data breaches and other security incidents. Improper authorization can lead to unauthorized information disclosure, modification, or destruction of data. In fact, faulty access control is the most common cause of security issues in web applications as identified in the OWASP Top Ten. In addition to proper authentication, it is important to properly implement authorization mechanisms to reliably determine what a user has access to.

You can choose from various authorization methods, including access control lists, role-based access control, and attribute-based access control. The appropriate authorization method to use depends on the specific requirements of your system or application and the level of security you require.

Access control lists

Access control lists (ACLs) define a list of users and the resources, data, or functionality they are authorized to access. Access-controlled resources could include files, directories, or specific web pages. If a user attempts to access a resource that is not included in the ACL, the user will be denied access.

One of the most attractive features of ACLs is that they allow you to control access on a per-resource basis. However, ACLs quickly become difficult to manage in environments where there is a large number of users and resources.

Role-based access control

Role-based access control (RBAC) grants or denies access to resources by assigning roles to users based on their job responsibilities and granting permissions to those roles. For example, in many software systems, users with an admin role have access to resources or functionality that regular users do not have access to. RBAC is commonly used in enterprise systems and applications to manage access to resources based on a user’s job responsibilities.

RBAC is a more flexible and scalable authorization method relative to ACLs. Since you can assign access rights to groups of users with similar roles, you can easily give access rights to new users by adding them to a group without needing to change and manage individual user permissions. If you need more granular access control that more accurately reflects the needs of individual users or specific scenarios, then you should consider attribute-based access control.

Attribute-based access control

Attribute-based access control (ABAC) grants or denies access to resources based on user attributes such as location, job title, security clearance level, and time of day. ABAC is a granular and flexible authorization method that enables you to use a wide range of user characteristics and context to determine what a user should have access to. Such granularity also enables you to support dynamic access control that allows access to be granted or denied based on real-time changes in user attributes or environmental conditions. However, with this level of granularity comes increased implementation and management complexity relative to other authorization methods.

Differences between authentication and authorization

It’s important for you to understand the differences between authentication and authorization in order to apply them properly to your specific scenario. As described above, authentication focuses on verifying the identity of a user or device while authorization grants or denies access to resources based on the verified user identity and the permissions assigned to that identity.

Authentication typically occurs at the beginning of a user session to ensure that only users or devices with verified identity are granted access to a software system. Authorization is a continuous process that occurs throughout the user session to ensure that users are able to access only the specific data or functionality that is appropriate for them. Authentication is typically a prerequisite for authorization since access to resources is often granted only to users who have already been authenticated and verified. Furthermore, authentication is usually a binary decision (i.e., the user is either authenticated or not), whereas authorization is typically more granular and controls access at a more fine-grained level.

Although authentication and authorization are distinct processes, they work together to ensure the security and integrity of software systems. You can use authentication and authorization in various software systems, including web applications, mobile applications, and enterprise systems. The following are some examples of authentication and authorization scenarios:

  • In an electronic health records system, you could use authentication to verify the identity of a physician before allowing them to access patient records. You could use authorization to control the level of access that a nurse has to specific patient records.
  • In a banking system, you could use authentication to verify the identity of a customer and use authorization to determine what kinds of reports the customer has access to depending on whether they have a checking account or a brokerage account.
  • In an inventory management system, you could use authentication to verify the identity of an employee before allowing them to access inventory data and update stock levels. After the user is authenticated, you could use authorization to differentiate between a warehouse supervisor who has access to inventory reports and a shipping clerk who has access only to shipping data.


In this article, you learned the differences between authentication and authorization, the different methods that can be used to implement them, and how they work together to verify users’ identity and control which resources, data, or functionality each user can access.

Understanding the subtle differences between authentication and authorization is crucial if you are looking to maintain the security and integrity of your systems and data. By implementing proper authentication and authorization measures, you can reduce the risk of security incidents and increase user confidence in your products and services.


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