The Duende.IdentityModel package is the base library for OIDC and OAuth 2.0 related protocol operations. It provides an object model to interact with the endpoints defined in the various OAuth and OpenId Connect specifications in the form of types to represent the requests and responses, extension methods to invoke requests constants defined in the specifications, such as standard scope, claim, and parameter names, and other convenience methods for performing common identity related operations.
Duende.IdentityModel targets .NET Standard 2.0, making it suitable for .NET and .NET Framework.