Is LDAP Single Sign-On?

When exploring enterprise identity solutions, terms like LDAP and Single Sign-On (SSO) frequently appear, often in close proximity, and sometimes used interchangeably. But are they the same? The short answer is no, LDAP is not Single Sign-On. However, the two can and often do work together to streamline authentication and access control across enterprise environments.

In this article, we’ll unpack what LDAP and SSO each mean, how they differ, and how they can be integrated to deliver secure, seamless access for users.

What Is LDAP?

LDAP stands for Lightweight Directory Access Protocol. It’s a protocol used to access and manage directory services over a network. Think of a directory service as a database optimised for reading, searching, and retrieving information, often used to store user credentials, group memberships, email addresses, and other identity-related data.

The most common implementation of an LDAP-based directory is Microsoft Active Directory (AD), although other versions like OpenLDAP are also widely used.

In practical terms, LDAP enables systems and applications to authenticate users by checking their credentials (typically a username and password) against a central directory. It acts as a gatekeeper, ensuring that users are who they say they are.

What Is Single Sign-On (SSO)?

Single Sign-On (SSO) is a separate concept. It’s an authentication process that allows users to log in once and gain access to multiple systems or applications without needing to authenticate again during the same session.

With SSO in place, users avoid the burden of managing multiple passwords and logins, reducing friction and improving security by encouraging the use of stronger authentication mechanisms (such as MFA) at the single point of entry.

SSO typically relies on technologies such as SAML (Security Assertion Markup Language), OAuth, or OpenID Connect, and integrates with Identity Providers (IdPs) that manage authentication flows centrally.

How LDAP and SSO Work Together

While LDAP and SSO are different, they are highly complementary and often work in tandem to provide a unified access experience.

Here’s how the integration typically works:

• User Authentication: When a user tries to access an SSO-protected application, the SSO system first needs to verify their identity.
• Backend Identity Verification via LDAP: The SSO solution queries the LDAP directory (such as Active Directory) to authenticate the user – essentially checking the credentials stored in the directory.
• Token-Based Access: Once authenticated, the SSO solution issues an access token (e.g. a SAML assertion or JWT), which allows the user to access other connected applications without needing to log in again.

This setup allows organisations to leverage existing LDAP infrastructure (e.g. Active Directory) for identity verification, while enabling modern SSO capabilities across cloud and on-premise applications.

Common Use Cases: LDAP + SSO

Many enterprises deploy SSO solutions that integrate directly with LDAP-based directories like Active Directory. This integration:

• Simplifies user experience by reducing password fatigue
• Enhances security by centralising authentication and enabling stronger MFA controls
• Streamlines IT operations by reducing helpdesk requests for password resets
• Supports hybrid environments where cloud apps and on-prem systems need unified access control

SSO providers My1Login enable seamless integration with LDAP directories, making it easy to deploy enterprise-grade SSO while maintaining compatibility with existing infrastructure.

LDAP and Single Sign-On serve distinct but interconnected roles in enterprise identity management. LDAP is a protocol for accessing and managing identity data, while SSO is a framework for streamlining user authentication. Together, they form a powerful combination – allowing organisations to improve security, enhance user productivity, and reduce operational overhead.

For businesses seeking secure, scalable identity management that works with existing directories, integrating LDAP with SSO is not only possible, it’s best practice.