LDAP Integration with OpenID Provider

LDAP (Lightweight Directory Access Protocol) and OpenID Connect are two distinct technologies used for identity management and authentication, but they can be integrated to provide a comprehensive solution for managing user identities and authentication processes. Here’s how LDAP can interact with OpenID Connect:

Using LDAP as a User Store for OpenID Provider:

• An OpenID Provider (OP) can use an LDAP directory as its backend user store. In this scenario, the OP interacts with the LDAP directory to authenticate users and retrieve user attributes.
• When a Relying Party (RP) requests authentication, the OP processes the authentication request by querying the LDAP directory.
• Upon successful authentication, the OP issues an ID token and possibly an access token to the RP.

LDAP Authentication via OpenID Provider:

• When a user attempts to log in, the OpenID Provider uses LDAP to verify the user’s credentials.
• The OP sends an LDAP bind request with the user’s credentials to the LDAP server.
• If the credentials are valid, the LDAP server responds with a success message, and the OP proceeds to generate the authentication tokens.

User Information Retrieval:

• The OpenID Provider can retrieve additional user information from the LDAP directory after authentication. This information can be included in the ID token or provided via the UserInfo endpoint.
• This process involves the OP querying the LDAP directory to fetch user attributes such as email, display name, group role etc…

Practical Example:

Let’s consider an enterprise environment where LDAP (e.g., Microsoft Active Directory) is used for internal user management, and the company wants to implement single sign-on (SSO) using OpenID Connect.

User Login:

• The user attempts to log in to a web application (RP) that supports OpenID Connect.
• The RP redirects the user to the OpenID Provider for authentication.

LDAP Authentication:

• The OpenID Provider receives the authentication request and collects the user’s credentials.
• The OP sends an LDAP bind request to the LDAP server with the provided credentials.
• The LDAP server authenticates the user and responds to the OP.

Token Issuance:

• If the LDAP authentication is successful, the OP generates an ID token and possibly an access token.
• The OP sends the authentication response, including the tokens, back to the RP.

User Info Endpoint:

• The RP can use the access token to request additional user information from the OP’s UserInfo endpoint.
• The OP queries the LDAP directory for the requested user attributes and responds to the RP with the user information.

Benefits of Integration:

• Centralized User Management: LDAP provides centralized user management, while OpenID Connect offers a standardized way to authenticate users across multiple applications.
• Enhanced Security: By using an OpenID Provider with LDAP as the backend, organizations can enforce strong authentication mechanisms and secure token-based access.
• Simplified SSO: Users can log in to multiple applications using a single set of credentials managed in LDAP, facilitated by OpenID Connect.