January 16, 2024

Single sign-on (SSO) is a popular authentication system in today’s digital world, as organizations are relying on a growing number of cloud applications and services. SSO is a great solution if you’re looking to simplify credential management, provide seamless and secure access to users, and streamline some IT processes.

Many service providers (such as SaaS solutions) and identity providers support protocols such as Secure Assertion Markup Language (SAML) and Lightweight Directory Access Protocol (LDAP), among others—but which one is best for your use case? Let’s take a look at SAML SSO vs. LDAP.

What is LDAP?

One of the oldest and most established identity management protocols, LDAP is used for accessing directory services. A client-server protocol, it typically runs on TCP/IP to send messages between the server and the client application. LDAP traffic is not encrypted by default, and many organizations choose to upgrade to LDAPS, or LDAP over SSL/TLS.

As a broad and robust solution, LDAP can be used both for authentication and authorization, which is why many IT admins rely on LDAP as a central hub for identity management. The protocol can be executed with either login credentials or digital certificates.

Advantages and disadvantages

Many service providers support an LDAP identity provider for SSO. This enables an organization to leverage its existing LDAP directory service to manage users for SSO.

LDAP’s disadvantage, however, is that the software was not designed to work natively with web applications. Developed in the early ‘90s, when the internet was just emerging, LDAP is more suitable for use cases such as Microsoft Active Directory and on-premises deployments.

With IT admins increasingly giving preference to newer authentication standards, some service providers are deprecating support for LDAP. When evaluating SAML SSO vs. LDAP options for your organization, such potential transitions should be among the criteria to consider.

What is SAML SSO?

An open standard that’s widely applied for SSO, SAML uses extensible markup language (XML) for communicating between the identity provider and the service provider. This authentication protocol eliminates the need for passwords because it relies on secure tokens—XML certificates that are encrypted and digitally signed.

SAML itself doesn’t perform the authentication but rather communicates the assertion data. It works in conjunction with LDAP, Active Directory, or another authentication authority, facilitating the link between access authorization and LDAP authentication.

Advantages and disadvantages

Versatile, lightweight, and available on most platforms, SAML 2.0 (the current version) is the most established standard for cloud and web applications, and is a common choice for centralized identity management.

While generally a secure protocol, SAML is not without security risks, such as XML attacks and DNS spoofing. If you’re planning to adopt SAML, implementing mitigation protocols is a critical step.


A discussion of authentication protocols wouldn’t be complete without a mention of OpenID Connect (OIDC). The newest among these three protocols, OIDC is growing rapidly in popularity and may be a better choice for some organizations.

OIDC is an authentication layer on top of Oauth 2.0, a simple, open authorization protocol that provides access without requiring users to share login credentials. Unlike SAML, OIDC uses REST/JSON, which means the protocol can be applied not only to the same use cases as SAML but also to mobile apps.

While some consider OIDC more secure than SAML, OIDC is not without risks. If the central account is compromised, for example, all the other accounts across platforms are at risk as well.

Final thoughts

While LPAD and SAML work differently, they’re not mutually exclusive and you can implement both in your environment. LPAD and SAML are only two of the major authentication protocols available, so it’s prudent to evaluate all the options before deciding which ones are best suited for your identity and access management (IAM) strategy.

Implementing SSO protocols can be complicated, especially if you have a complex ecosystem. Learn about how SailPoint integrates with the top access management solutions.

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