Security Assertion Markup Language (SAML) defines a common XML framework for creating, requesting, and exchanging authentication and authorization data among entities known as Identity Providers (IdPs) and Service Providers (SPs). This exchange enables single sign-on among such entities.

• IdP is a system or administrative domain that asserts information about a subject. The information that an IdP asserts pertains to authentication, attributes, and authorization. An assertion is a claim that an IdP makes about a subject.
• Service Provider is a system or administrative domain that relies on information provided by an IdP. Based on an assertion from an IdP, a service provider grants or denies access to protected services.

In simple terms, an IdP is a claims producer and a service provider is a claims consumer. An IdP produces assertions about users, attesting to their identities. Service providers consume and validate assertions before providing access to resources.

SAML 2.0 is an OASIS open standard. The SAML core specification defines the structure and content of assertions.

SAML metadata specifies how configuration information is defined and shared between two communicating entities: a SAML Identity Provider (IdP) and a SAML service provider. Service provider metadata provides information about service provider requirements, such as whether the service provider requires a signed assertion, the protocol binding support for endpoints (AssertionConsumerService) and which certificates and keys to use for signing and encryption. IdP metadata provides information about IdP requirements, such as the protocol binding support for endpoints (SingleSignOnService), and which certificate to use for signing and encryption.

Single logout (SLO) service is a way to allow a user to terminate all sessions in an automatic manner without user intervention. A SAML Identity Provider (IdP) or the SAML service provider (SP) can initiate logout. The SAML IdP coordinates all logouts. When a SAML SP initiates a logout it contacts the SAML IdP to carry out the coordinated logout on its behalf.

Access Policy Manager (APM) supports SLO when all participating entities (SAML SPs and IdPs) support SLO. APM supports HTTP-POST binding for SLO messages.

Access Policy Manager as a SAML Identity Provider (IdP)

When you use Access Policy Manager(APM) as a SAML IdP, APM can authenticate and generate assertions for a user who can then gain access to resources protected by SAML. APM provides SAML assertions (claims) that service providers verify and consume. In this role, APM acts as an authentication server and provides single sign-on to service provider resources.

Access Policy Manager as a SAML Service Provider (SP)

When you use APM as a SAML service provider, APM consumes SAML assertions (claims) and validates their trustworthiness. After successfully verifying the assertion, APM creates session variables from the assertion contents. In an access policy, you can use these session variables to finely control access to resources and to determine which ACLs to assign. Based on the values of session variables, you can create multiple branches in the policy, assigning different resources and different ACLs on each branch. When it runs, the access policy follows a branch depending on the values of session variables.

Federation

APM systems operate with one another when one APM system is configured as an IdP and other APM systems are configured as service providers. This allows a user to authenticate with one APM acting as an IdP, and then use any number of APM systems, serving as service providers, without having to re-authenticate.

Metadata import and export

You can simplify SAML configuration using metadata files. When you use APM as an IdP, you can configure a SAML service provider by importing a metadata file that you obtain from the vendor. Similarly, when you use APM as a service provider, you can configure an IdP by importing a metadata file that you obtain from the vendor. You can export the metadata for APM as a SAML IdP from APM and import the metadata file into a service provider (or use information from the metadata file to configure the service provider). You can export the metadata for APM as a SAML service provider from APM and import the metadata file into an IdP (or use information from the metadata file to configure the IdP).

Templates

APM provide a few templates that you can use to create service provider connectors and a few that you can use to create IdP connectors with a minimal amount of typing.

Custom service providers and custom IdPs

In addition to configuring service provider connectos or an IdP connector from vendor metadata files or APM templates, you can configure custom service provider and IdP connectors.

IdP-initiated and service provider-initiated client connections

Access Policy Manager supports client connections that initiate at the IdP or at the service provider.

Signed assertions

By default, APM produces signed assertions. An assertion signed by the asserting party (the IdP) supports assertion integrity, authentication of the asserting party to a SAML relying party (a service provider), and, if the signature is based on the SAML authority’s public-private key pair, non-repudiation of origin.

Encrypted assertions

For increased security, APM can optionally encrypt the entire assertion. APM supports encryption methods AES128, AES192 and AES256.

Support for SAML profiles

APM supports the Web Browser SSO profile with HTTP redirect and HTTP POST bindings.

Configure a BIG-IP system as a SAML identity provider (IdP) when you have one BIG-IP system and you want it to provide single sign-on authentication service for a group of external SAML service providers.

Configure a BIG-IP system as a SAML service provider when you have one BIG-IP system and you want it to protect services that are behind it, and direct users to an external SAML identity provider for authentication.

For security purposes, each SAML service provider (SP) should have a certificate from the SAML Identity Provider (IdP) that manages identities for it; each IdP should have certificates from the SPs for which it manages identities.