Top 20 NuGet authentication Packages

Kerberos authentication support for the AMPS C# Client.
JWT Authentication Plugin for Asp.Net Core Identity
ASP.NET Core contains middleware to support Kodulars OAuth 2.0 authentication workflow.
Xbox Live authentication for .NET
Versatile OpenID Connect stack for OWIN/Katana (compatible with ASP.NET 4.6.1 and newer).
OWIN/Katana integration package for the OpenIddict server services (compatible with ASP.NET 4.6.1 and newer).
OWIN/Katana integration package for the OpenIddict validation services (compatible with ASP.NET 4.6.1 and newer).
SAML 2.0 (SAML2P) identity provider functionality. Requires the addition of Rsk.Saml.DuendeIdentityServer.
SimpleAuthentication is a ASP.NET library that makes it really simple to for developers to add Social Authentication code to an ASP.NET application.
Claims-based user account and identity management framework
Delegation Handler based Authentication Framework for ASP.NET Web API v2.
A token based authentication provider for Nancy.
Scope-based Authorization for Web API v2.
OWIN middleware implementation mixing Windows and Forms Authentication.
A scaffold for building an application with Zurb for Applications and .Net that includes OWIN Token based authentication.
RavenDB user/role store management implementation for ASP.NET Core identity provider.
Adds OpenId Auth Providers for use in StackExpress Web and REST Services. Includes built-in support for Google, Yahoo, MyOpenId and Custom OpenId providers. More Info on Auth Providers: https://github.com/ServiceStack/ServiceStack/wiki/Authentication-and-authorizat...
ASP.NET Core types and middlewares to accept tokens from Azure B2C and Azure AD tenants. For more info, see the project url
A Cross Platform OTP (TOTP HOTP) Library for .NET Core NetStandard
ASP.NET Core security middleware enabling Alipay authentication.