Federation is a method for enabling secure communication and sharing of data between different systems or applications. In the context of authentication, federation refers to the process of allowing users to use their existing credentials from one system to access another system, without having to create a new set of credentials for that system.
Federation is typically implemented using a standard protocol, such as Security Assertion Markup Language (SAML) or OpenID Connect (OIDC), and involves a set of components working together to facilitate authentication and authorization. In this blog post, we will explore how federation works in authentication, provide an example workflow, and discuss some of the tools used to implement federation.
How Federation Works in Authentication
In a federated authentication scenario, a user attempts to access a resource on a target system. The target system, which may be a web application, a network resource, or a cloud service, requires the user to authenticate before granting access to the resource. Instead of prompting the user to enter a set of credentials specific to the target system, the target system redirects the user to an identity provider (IdP).
The identity provider is the system that the user originally authenticated with, and it is responsible for verifying the user’s identity and providing a set of claims about the user, which include information such as the user’s name, email address, and group membership. The identity provider may also provide information about the user’s authentication method, such as whether the user authenticated using a password, a smart card, or biometrics.
Once the identity provider has verified the user’s identity, it generates a security token that contains the user’s claims and signs the token using a digital signature. The token is then returned to the target system, which verifies the digital signature and the claims in the token to ensure that the user is authorized to access the resource.
Federation relies on trust relationships between the target system and the identity provider. These relationships are established through a process known as federation metadata exchange, which involves exchanging metadata that describes the protocols, endpoints, and certificates used by the target system and the identity provider.
Example Workflow
To better understand how federation works in authentication, let’s walk through a simple example workflow.
- The user attempts to access a resource on a target system.
- The target system redirects the user to an identity provider, which may prompt the user to authenticate using a password or some other authentication method.
- Once the user is authenticated, the identity provider generates a security token that contains the user’s claims and signs the token using a digital signature.
- The identity provider returns the security token to the target system.
- The target system verifies the digital signature and the claims in the security token to ensure that the user is authorized to access the resource.
- If the user is authorized, the target system grants access to the resource.
Tools Used in Federation
Several tools are used to implement federation, including:
SAML
SAML is an XML-based standard for exchanging authentication and authorization data between parties, in particular, between an identity provider and a service provider. SAML defines a protocol for the exchange of security tokens, such as authentication assertions, between parties. SAML is widely used in enterprise environments, particularly in government and healthcare.
OpenID Connect
OpenID Connect is an authentication protocol built on top of the OAuth 2.0 authorization framework. OpenID Connect allows for the exchange of authentication and authorization data between parties, including identity providers and service providers. OpenID Connect is designed to be easy to use and is rapidly gaining popularity in the web and mobile application space.
Identity Providers
Identity providers are the systems that provide authentication and authorization services to users. Common examples of identity providers include Microsoft Active Directory, Google, Okta, and Ping Identity.
Service Providers
Service providers are the systems or applications that require users to authenticate in order to access resources or services. Common examples of service providers include Salesforce, Dropbox, and Amazon Web Services.
Federation Metadata
Federation metadata is an XML document that describes the endpoints, certificates, and protocols used by a service provider and an identity provider. This metadata is used to establish trust between the two parties and to enable secure communication between them.
Federation Servers
Federation servers are systems that facilitate the exchange of security tokens between identity providers and service providers. Federation servers can act as intermediaries between the two parties, handling the exchange of metadata and security tokens and providing additional security features such as token signing and encryption.
Single Sign-On (SSO)
Single sign-on is a feature of federation that allows users to log in once and access multiple systems or applications without having to re-enter their credentials. SSO is enabled by the exchange of security tokens between identity providers and service providers and is an important feature of many enterprise environments.
Conclusion
Federation is a powerful tool for enabling secure communication and sharing of data between different systems or applications. In the context of authentication, federation allows users to use their existing credentials from one system to access another system, without having to create a new set of credentials for that system. Federation is typically implemented using a standard protocol such as SAML or OpenID Connect and involves a set of components working together to facilitate authentication and authorization. By understanding how federation works in authentication and the tools used to implement it, organizations can build secure and scalable authentication solutions that meet their specific needs.
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