# Yubikey

> YubiKey hardware security key reference. Covers FIDO2 passkeys, U2F two-factor, TOTP authenticator codes, GPG smartcard for commit signing, ed25519-sk SSH keys, PIV certificates, ykman CLI, OTP slots, PIN management, and model comparison.

- Skill: `bytesagain/yubikey` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add bytesagain/yubikey`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bytesagain/yubikey/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: bytesagain (https://skillmd.com/u/bytesagain)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/bytesagain/yubikey

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# YubiKey Reference

Hardware security key.

## Commands

| Command | Description |
|---------|-------------|
| `intro` | Models, protocols |
| `setup` | Passkeys, TOTP, U2F |
| `advanced` | GPG, SSH, PIV |