# google/OpenSK

OpenSK is an open-source implementation for security keys written in Rust that supports both FIDO U2F and FIDO2 standards.

Repository: https://github.com/google/OpenSK
Canonical: https://ross.abutalabs.com/products/opensk
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: fido2, u2f, security-key, rust, tock, firmware, embedded, hardware, security, webauthn, ctap2, tock-os, opensk
Last push: 2026-08-06T08:22:13+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 96, release rhythm 8, longevity 100
- inputs: {"age_days": 2451, "days_push": 27, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3404, forks 334 (observed 2026-08-28T04:08:03.001075+00:00)

## What it is
OpenSK is an open-source Rust implementation of a FIDO2/FIDO U2F security key, developed by Google as a research platform. It can run as firmware on Nordic nRF52840 hardware, as a Wasefire applet, or as a library.

## Use cases
- build my own open-source FIDO2 security key
- implement CTAP2/WebAuthn authenticator firmware in Rust
- research hardware two-factor authentication tokens
- flash a FIDO U2F key onto a Nordic nRF52840 dongle
- experiment with hardware-backed passkey authentication
- study certified security key implementations

## When to choose
- you want a fully open-source security key stack from OS to application
- you need a Rust codebase for FIDO2/CTAP research or prototyping
- you have supported hardware like the nRF52840-DK or dongle

## When to avoid
- you need a production-ready, FIDO-certified key for daily use (the develop branch is explicitly proof-of-concept)
- you want a turnkey consumer security key without hardware work
- you need certified CTAP 2.1+ features, since the develop branch is not FIDO certified

## Facets
- artifact type: library
- maturity: active
- function: security, cryptography, auth, embedded
- domain: security, embedded-systems, hardware
- platform: embedded, rust
- tags: fido2, u2f, webauthn, ctap2, security-key, firmware, tock-os, nrf52840, two-factor-authentication, passkeys, authentication

## Member repositories
- google/OpenSK (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:03.001075+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 2026-08-29T18:38:37.336076+00:00, confidence not recorded.
  - readme: https://github.com/google/OpenSK (fetched 2026-08-28T04:08:03.001075+00:00, sha b188909dcb1c)
- Data as of 2026-08-30T08:39:29.467469+00:00.