Category Security

ASP.NET Core delegated Microsoft OBO access token management (Entra only)

This blog shows how to implement a delegated Microsoft On-Behalf-Of flow in ASP.NET Core, and has a focus on access token management. The solution uses Microsoft.Identity.Web to implement the different flows and it really simple to implement, when you know how to use the Nuget package and use the correct Microsoft documentation. The application can […]

Use client assertions in OpenID Connect and ASP.NET Core

Client assertions is a method of client authentication which can be used in OpenID Connect. This provides an alternative to client secrets. This approach enhances security by using signed tokens (JWTs) to authenticate clients during the token request process or the OAuth PAR request. In ASP.NET Core, client assertions is not supported per default, a […]

Customizing a single client sign-in using parameters in Duende IdentityServer

This post looks at customizing the sign-in UI and the sign-in options in an ASP.NET Core application using Duende IdentityServer and ASP.NET Core Identity. There are multiple ways of changing the look and feel of the UI for different OpenID Connect clients or different client flows. In the previous post, the UI was customized per […]

ASP.NET Core delegated OAuth Token Exchange access token management

This blog shows how to implement a delegated OAuth 2.0 Token Exchange RFC 8693 flow in ASP.NET Core, and has a focus on access token management. It looks at how the OAuth Token Exchange can be implemented and how an application can request delegated access tokens on behalf of a user and another application, providing […]

ASP.NET Core user application access token management

This article looks at management application access tokens in an ASP.NET Core web application. Any application with or without a user can use application access tokens as long as the application can persist the tokens in a safe way. Code: https://github.com/damienbod/token-mgmt-ui-application Blogs in this series Setup The ASP.NET Core web application authenticates using OpenID Connect […]

Using Entra External ID with an Auth0 OpenID Connect identity provider

This post looks at implementing an Open ID Connect identity provider in Microsoft Entra External ID. Auth0 is used as the identity provider and an ASP.NET Core application is used to test the authentication. Microsoft Entra External ID federates to Auth0. Client code: https://github.com/damienbod/EntraExternalIdCiam Microsoft Entra External ID supports federation using OpenID Connect and was […]

ASP.NET Core and Angular BFF using a YARP downstream API protected using certificate authentication

This article demonstrates how to implement a downstream API protected by certificate authentication using Microsoft YARP reverse proxy in an ASP.NET Core web application. The application uses Angular for its UI and secures both the UI and the ASP.NET Core backend through a backend-for-frontend security architecture. The downstream API is secured with certificate authentication and […]

Implement security headers for an ASP.NET Core API supporting OpenAPI Swagger UI

This article shows how to implement security headers for an application supporting an API and a swagger UI created from a open API in .NET 9. The security headers are implemented using the NetEscapades.AspNetCore.SecurityHeaders Nuget packages from Andrew Lock. Code: https://github.com/damienbod/WebApiOpenApi Deploying a web application which supports both an API and a UI have different […]

Implement OpenID Connect Back-Channel Logout using ASP.NET Core, Keycloak and .NET Aspire

This post shows how to implement an OpenID Connect back-channel logout using Keycloak, ASP.NET Core and .NET Aspire. The Keycloak and the Redis cache are run as containers using .NET Aspire. Two ASP.NET Core UI applications are used to demonstrate the server logout. Code: https://github.com/damienbod/keycloak-backchannel Setup The applications are run and tested using .NET Aspire. […]

Implement ASP.NET Core OpenID Connect OAuth PAR client with Keycloak using .NET Aspire

This post shows how to implement an ASP.NET Core application which uses OpenID Connect and OAuth PAR for authentication. The client application uses Keycloak as the identity provider. The Keycloak application is hosted in a docker container. The applications are run locally using .NET Aspire. This makes it really easy to develop using containers. Code: […]