SAML: How It Works and How to Implement It

What Is SAML?

SAML is an open standard written in XML and the foundation of single sign-on capabilities. It eliminates the need for users to sign in and out with unique credentials for every application they are provisioned to use, while maintaining security and control over access rights.

It also decouples the identity provider from the service provider, which is key to powering SSO for users. 

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How Does a SAML Authentication Work?

A SAML authentication operates through a federated identity model. An identity provider (IDP) verifies a user’s identity and issues authentication tokens, while the service provider (SP) grants access based on that verification.

“SAML allows an application or system, the service provider, to authenticate a user via an intermediary party, the identity provider,” says Geoff Cairns, principal analyst for security and risk at Forrester.

The IDP is responsible for verifying the identity of users and issuing authentication tokens, or SAML assertions, to vouch for their identity when they attempt to access a protected resource.

The authentication flow begins when a user requests access to an SP-protected resource. If that user is not already authenticated, the SP redirects them to the IDP, where they log in using their credentials.

Then, the IDP validates the user’s information and generates a SAML assertion containing key details such as name, email and roles. This assertion is sent back to the SP, which verifies its authenticity before granting access.

“If the SAML assertion is valid, the service provider allows the user to access the requested resource,” Cairns explains. “This entire process enhances security by centralizing authentication while also improving user experience through SSO.”

How Does Federated Identity Fit In?

Federated identity allows users to access multiple applications or services across different organizations or domains using a single set of credentials.

“It requires a trust relationship between entities,” Cairns says. “That trust relationship is established through SAML’s set of cryptographic keys and authentication protocols.”

In a federated SSO setup, an employee at Agency A can use their work credentials to access a partner system at Agency B, as long as Agency B securely verifies their identity through the federation.

For Carla Roncato, vice president of identity at WatchGuard, the central idea is the portability and reusability of digital identities. “The goal is to enable users of one domain to securely access applications, data and systems in a seamless way without redundant user management,” she says.

How Agencies Can Plan for a Successful SAML Deployment

A successful SAML deployment requires careful planning, selecting the right IDPs and SPs so that there is seamless interoperability between systems. 

According to Trevor Thompson, principal software architect for Okta, agencies must start by choosing platforms that effectively support SAML. “You’ll find differing levels of maturity across systems,” he says. “You must choose systems that will interoperate well.”

Configuration also plays a crucial role, particularly in mapping out metadata exchanges. “SAML is a pretty old protocol, so the setup process and metadata exchange are manual, requiring administrators to understand and configure these elements properly,” Thompson says. 

Government agencies should also consider security settings such as encryption and signing algorithms, he says, to ensure compatibility between IDPs and SPs.

EXPLORE: Continuous authentication builds a zero-trust foundation for state and local agencies.

Then, test and monitor all configurations before a full deployment. “All of this setup has to be done, and then you have to test it and make sure it works for all users before rolling it out in production,” Thompson explains.

And once the connections are solid, teams can browse from a catalogue of SAML-capable applications to offer users a customized look and feel, Roncato notes. 

“This makes all the difference in providing the best UX experience, as it tells users they are accessing a familiar and inherently trustworthy environment from wherever they work,” she says.

A Few Best Practices for Implementation

Successful SAML implementation requires careful planning and collaboration across multiple stakeholders to ensure seamless authentication and security.

Cairns recommends that agencies involve security architects, IT and identity and access management teams, application owners, developers, and legal/compliance teams early in the process.

“Planning and collaboration are crucial to success, and stakeholders from across the organization need to be involved,” Cairns says.

This cross-functional approach helps ensure that SAML integrates smoothly with applications while maintaining compliance with data protection regulations.

Agencies must also decide on the right implementation model. While some agencies still have on-premises systems, most states and major cities have migrated at least some of their infrastructure into the cloud. 

“Since many applications are SaaS-based, cloud SSO is now the preferred approach for most organizations,” she explains.

Implementing SAML through a service provider allows users to initiate authentication requests directly from an application or portal, while identity providers validate user credentials before granting access.

Roncato adds that implementing SAML through a token provider that supports multifactor authentication ensures that authentication requests are verified before access is granted.

This extra layer of validation helps protect against unauthorized access, allowing agencies, especially those in hybrid IT environments, to access cloud and on-premises applications through secure digital identities.

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