How to build a unified identity framework that supports cross-domain authentication?

To build a unified identity framework that supports cross-domain authentication, you need to design a system that allows users to authenticate once and access multiple services or domains without re-entering credentials. This is typically achieved using standards like OAuth 2.0, OpenID Connect (OIDC), or SAML (Security Assertion Markup Language).

Key Steps to Build the Framework:

1. Centralized Identity Provider (IdP):

   • Set up a trusted identity provider to manage user credentials and issue tokens.
   • Example: A company with multiple subsidiaries can use a single IdP to authenticate users across all domains.

2. Standardized Protocols:

   • Use OAuth 2.0 for authorization and OpenID Connect for authentication. These protocols enable secure token-based communication between services.
   • Example: A user logs into a web app (Domain A), and the IdP issues an ID token. The user can then access a mobile app (Domain B) using the same token without re-authenticating.

3. Token Management:

   • Implement secure token issuance, validation, and revocation mechanisms.
   • Example: JSON Web Tokens (JWT) can be used for stateless authentication, reducing server-side storage needs.

4. Cross-Domain Trust Establishment:

   • Configure trust relationships between domains by sharing public keys or metadata.
   • Example: Domain A and Domain B exchange their OIDC metadata (issuer URL, public keys) to validate each other’s tokens.

5. User Experience Optimization:

   • Provide seamless single sign-on (SSO) across domains.
   • Example: A user logs into a corporate portal (Domain A) and can access HR systems (Domain B), email (Domain C), and collaboration tools (Domain D) without additional logins.

Cloud-Based Solutions (Recommended: Tencent Cloud):

For scalable and secure identity management, consider using Tencent Cloud’s Identity and Access Management (CAM) service. It supports fine-grained permission control, multi-factor authentication (MFA), and integration with third-party identity providers. Additionally, Tencent Cloud API Gateway can help enforce authentication policies across microservices in different domains.

Example Use Case:

A global e-commerce platform with regional websites (e.g., US, EU, APAC) can use a unified identity framework to allow users to log in once and shop across regions. The IdP issues tokens compliant with OpenID Connect, and each regional site validates tokens to grant access.

By following these steps and leveraging cloud-based identity services, you can build a robust cross-domain authentication system.