# DotNetOpenAuth/DotNetOpenAuth

A C# implementation of the OpenID, OAuth protocols

Repository: https://github.com/DotNetOpenAuth/DotNetOpenAuth
Canonical: https://ross.abutalabs.com/products/dotnetopenauth
Homepage: http://dotnetopenauth.net
Language: C#
License: NOASSERTION
License Family: other
Archived: true
Last push: 2018-01-11T13:05:28+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 6739, "days_push": 3156, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1716, forks 718 (observed 2026-08-28T04:05:26.349754+00:00)

## What it is
DotNetOpenAuth is a C# library implementing the OpenID and OAuth protocols for .NET applications. It lets developers build both Identity Providers and Relying Parties (consumers), supporting OpenID 1.x/2.0 and OAuth 1.0/1.0a/2.0.

## Use cases
- add OpenID login to an ASP.NET website
- implement an OAuth authorization server in C#
- build an OAuth client for a .NET desktop or web app
- host an OpenID provider so users get their own OpenIDs
- integrate federated identity into legacy ASP.NET WebForms or MVC apps

## When to choose
- you maintain a legacy .NET Framework / ASP.NET application needing OpenID or OAuth 1.0/2.0 support
- you need to act as both an OpenID provider and relying party in C#
- you need fine-grained control over OpenID extensions like Attribute Exchange or PAPE

## When to avoid
- you are starting a new .NET project - prefer modern libraries like ASP.NET Core authentication handlers or IdentityServer/OpenIddict
- you need active maintenance and recent security patches - the last release was in 2018
- you target .NET Core/.NET 5+ rather than the classic .NET Framework

## Facets
- artifact type: library
- maturity: maintenance
- function: auth, authorization, security
- domain: security, web-development, apis
- platform: dotnet, windows
- tags: openid, oauth, identity-provider, csharp, aspnet, legacy, web-server

## Member repositories
- DotNetOpenAuth/DotNetOpenAuth (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:26.349754+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:34:14.615408+00:00, confidence not recorded.
  - readme: https://github.com/DotNetOpenAuth/DotNetOpenAuth (fetched 2026-08-28T04:05:26.349754+00:00, sha 4fa5a82bdb50)
  - homepage: http://dotnetopenauth.net (fetched 2026-08-29T11:10:15.049256+00:00, sha 22420aaf3143)
- Data as of 2026-08-30T08:39:29.467469+00:00.