# passwordless-lib/fido2-net-lib

Passkeys, FIDO2 and WebAuthn .NET library.

Repository: https://github.com/passwordless-lib/fido2-net-lib
Canonical: https://ross.abutalabs.com/products/fido2-net-lib
Homepage: https://fido2.andersaberg.com
Language: C#
License: MIT
License Family: permissive
Topics: fido, webauthn, net-core, asp-net-core, fido2, passwordless, ctap, passkeys
Last push: 2026-04-20T15:45:25+00:00

## Health v2 (maintenance only)
Score: 71/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 78, release rhythm 46, longevity 100
- inputs: {"age_days": 3016, "days_push": 135, "days_rel": 149, "gap_med": 219, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1448, forks 201 (observed 2026-08-28T04:04:45.564989+00:00)

## What it is
A battle-tested .NET library implementing a FIDO2 server / WebAuthn relying party for passkey registration (attestation) and authentication (assertion) validation. It enables passwordless sign-in and strong MFA in ASP.NET, .NET Core, and native .NET applications.

## Use cases
- add passkey login to an asp.net core app
- implement webauthn passwordless authentication in .net
- verify fido2 attestation and assertion responses
- support yubikey and windows hello sign-in
- replace password-based login with phishing-resistant mfa
- build a fido2 server / webauthn relying party

## When to choose
- you need advanced FIDO2 features like attestation verification beyond .NET 10's built-in ASP.NET Identity passkey support
- you want a conformance-tested, battle-tested open-source WebAuthn implementation for .NET
- you need support for roaming authenticators, platform authenticators, and FIDO U2F backwards compatibility

## When to avoid
- your project is not on the .NET platform
- you only need simple passkey support inside ASP.NET Identity and don't need attestation or advanced features
- you want a hosted passwordless API service rather than a self-implemented relying party library

## Facets
- artifact type: library
- maturity: active
- function: auth, security, cryptography, sdk
- domain: security, web-development, backend, developer-tools
- platform: dotnet, cross-platform
- tags: fido2, webauthn, passkeys, passwordless, mfa, asp-net-core, ctap, authentication, web-server

## Member repositories
- passwordless-lib/fido2-net-lib (main) score 71

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:45.564989+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 2026-08-30T04:36:04.571967+00:00, confidence not recorded.
  - readme: https://github.com/passwordless-lib/fido2-net-lib (fetched 2026-08-28T04:04:45.564989+00:00, sha 6d550ee9a07c)
  - homepage: https://fido2.andersaberg.com (fetched 2026-08-29T11:45:46.680856+00:00, sha 24c6d581f04a)
- Data as of 2026-08-30T08:39:29.467469+00:00.