SAML vs. OAuth: What’s the Difference?

The main difference between Security Assertion Markup Language (SAML) and Open Authorization (OAuth) lies in their roles: SAML focuses on authentication, while OAuth is dedicated to authorization. Despite their differences, both SAML and OAuth are necessary for improving your organization’s overall security, allowing authorized users to verify their identities and access appropriate resources.

Continue reading to learn what SAML and OAuth are, their differences, their similarities and whether your organization should use them.

What is SAML?

Security Assertion Markup Language (SAML) simplifies the login process by allowing users to log in with one set of credentials and access multiple systems without reentering login credentials each time. SAML works by sending authentication information in a specific format between an Identity Provider (IdP) and a web application. When you try to log in, the web application that uses SAML for authentication asks the identity provider to authenticate your login credentials. Once you’ve entered your username and password, the IdP sends a special message called a SAML assertion to the web application, confirming that your identity has been verified. The IdP will send the SAML assertion to the original web application you wanted to log in to, which then evaluates the SAML assertion to grant you access. SAML simplifies the login process on multiple web applications, minimizing the time spent logging in to each application.

What is OAuth?

Open Authorization (OAuth) lets you share access to data with third-party applications without giving them access to your login credentials. Imagine you want to use an app that needs access to your camera roll stored in the cloud. The app will ask for permission to access that data, redirecting you to log in to your cloud storage provider. Once you log in, you will be asked if you want the app to have access to your camera roll. If you accept, the cloud service will create an access token, which grants the app access to your camera roll without revealing your login credentials. By granting access with a key instead of your password, you avoid sharing your login credentials with a third-party application. Instead, a third-party application will only have access to what you approve it to see.

The key differences between SAML and OAuth

Although both SAML and OAuth are important security protocols that your organization should implement to protect data, there are several major differences between the two.

SAML and OAuth have different use cases

SAML is designed for enterprise authentication, whereas OAuth is made for authorization between apps or services. When you want to log in to multiple services without entering your login credentials each time, SAML is especially useful in business environments. Let’s say your organization uses different apps for email, marketing, sales and HR. With SAML, if you log in once to your organization’s portal, you can access all necessary applications without needing to log in over and over.

OAuth helps keep your login credentials secure while sharing data with apps, such as on social media platforms or third-party services. For example, if you open an app for work that requires you to log in with your Google account, that app is using OAuth. This means the app can access your data without needing your password, once you authorize it to do so.

SAML and OAuth have different security models

SAML uses digital signatures and assertions to secure data, while OAuth relies on access tokens. SAML assertions confirm you are who you say you are by verifying your identity during the login process. They are often signed with digital signatures, which ensure that your information hasn’t been altered and can be trusted.

Instead of using assertions or digital signatures, OAuth uses tokens and scopes to authorize users. If you allow an app to access your data, it receives an access token that lets the app see your data without needing your login credentials. Scopes allow you to determine the type of access tokens have. OAuth grants specific permissions without sharing your password, emphasizing data integrity and limiting third-party apps to only the necessary data.

SAML and OAuth use different data formats

SAML uses XML-based assertions that contain detailed user attributes. SAML assertions in XML format include details about a user, when they last logged in and what they should have access to. Because XML is complex, it can be more challenging to read and manage, making it a better choice for large enterprises.

In contrast, OAuth uses JavaScript Object Notation (JSON) to represent data. Since JSON is easier to read than XML, this format is popular for data in web applications. OAuth access tokens are generally represented as JSON objects that specify when the token will expire, what permissions are granted and the type of token being used to access data. 

SAML is more complex to implement than OAuth

SAML relies on assertions to verify users’ identities and requires multiple systems to function simultaneously, which requires intricate configuration to ensure users are authenticated accordingly. In terms of security, SAML offers more extensive features, including digital signatures and encrypted assertions, which make implementing it more complex with multiple security layers.

OAuth is much more straightforward, mainly because it uses JSON for data representation instead of XML. Since JSON is simpler to read and more compact, it loads more easily and has less strict controls. Unlike SAML, OAuth requires fewer steps to set it up since all you need is the application and its defined permissions. Using access tokens rather than certificates or assertions makes OAuth easier to manage user permissions as well.

SAML and OAuth manage sessions differently

SAML creates browser sessions and handles logins across multiple applications. After you log in to an app through an IdP, a session is created that lets you access more than one app without needing to enter your login credentials each time.

This differs from OAuth, which uses access tokens to manage sessions. If you authorize an app, it receives a token that gives it access to your data for a limited time. If the app needs extended access, it can request a new access token without needing you to log back in.

What are the similarities between SAML and OAuth?

Despite SAML and OAuth having many key differences, they share several similar features:

• They are both open-standard frameworks, meaning they are based on security guidelines that any organization can implement.
• They both enable Single Sign-On (SSO), which allows you to access multiple apps or services with one set of login credentials. SAML and OAuth reduce how many times you have to enter your login credentials, saving time and minimizing security risks.
• They both support Federated Identity Management (FIM), allowing you to log in to multiple external services, such as applications from various organizations. SAML and OAuth enable access to several IT resources using a single set of login credentials, securing the login process through assertions and tokens.

Should your organization use SAML or OAuth?

Instead of choosing between SAML or OAuth, your organization should consider using them both, as they are not interchangeable protocols. Although SAML supports user authentication and authorization, it is still beneficial to use OAuth to manage user privileges. Using both SAML and OAuth will allow your organization to grant access to systems with SAML and to resources with OAuth.

The bottom line

Your organization could benefit from using both SAML and OAuth to protect your data from unauthorized users. SAML verifies users’ identities when accessing multiple services or apps, while OAuth authorizes apps to access your data without sharing your passwords. Implementing both SAML and OAuth can improve your overall security and user experience by spending less time logging in to multiple services and creating simpler interactions to secure data.

Curious to see how Keeper integrates with any SAML 2.0 compatible identity provider? Request a demo of Keeper SSO Connect^® to enhance your organization’s overall security.