How Can ASP.NET Core Authentication Be Designed for Modern Business Applications?

Modern authentication should be designed around trusted identity providers, standards-based protocols, token validation, and clearly separated authentication and authorization responsibilities. For enterprise ASP.NET Core applications, Microsoft Entra ID can provide identity management, while OpenID Connect is used for interactive user authentication and OAuth-based mechanisms are used when applications need access to protected APIs. Microsoft describes OpenID Connect as an identity layer built on OAuth 2.0. For Web APIs, developers commonly work with JWT bearer authentication. The API should validate important token properties such as the signature, issuer, audience, and expiration rather than simply trusting the presence of a token. Microsoft.Identity.Web provides integration between ASP.NET Core and Microsoft Entra ID and supports scenarios involving delegated permissions, application permissions, scopes, and authorization policies. A good learning exercise is to build a small business API where employees authenticate through Microsoft Entra ID, different users receive different permissions, and an API validates scopes or application permissions before allowing operations. This helps students understand the difference between “Who are you?” and “What are you allowed to do?”—one of the most important distinctions in enterprise application security.