Security Assertion Markup Language 2.0 (SAML) is an open federation standard that allows an identity provider (IdP) to authenticate users and pass identity and security information about them to a service provider (SP), typically an application or service. With SAML, you can enable a single sign-on experience for your users across many SAML-enabled applications and services. Users authenticate with the IdP once using a single set of credentials, and then get access to multiple applications and services without additional sign-ins. Because SAML-enabled applications delegate authentication to an IdP, the SP can automatically grant, revoke, or change the scope of a user’s access to applications and services when an administrator adds, removes, or modifies the user’s information in the IdP.
SAML (Security Assertion Markup Language) is one of the most secure way to integrate with third-party among many other options. It allows parties to use asymmetric encryption (RSA) based on secure X.509 certificates. As of 2021, the standard is in version 2.
Up until the past few years, SAML was considered the industry standard—and proven workhorse—for passing an authenticated user into applications while allowing these applications to defer authentication to a centralized identity solution. However, with the introduction of OpenID Connect, which is an authentication layer built on top of OAuth2, SAML has become outdated. Furthermore, every year seems to bring new issues with SAML – in the form of newly discovered exploits – which is giving it a reputation of not being the most secure option.