TurtleAuth: Let's Make a DIY GPG USB Key - Hackster.io
Nitrokey | Secure your digital life
Crypto-stick (OpenPGP USB stick) — insecure.ws
Secure Hardware vs. Open Source - Yubico
File:Gemalto usb shell token with a punched OpenPGP card inside.jpg - Wikimedia Commons
Open PGP SmartCard V2.1 ID-000
Gnuk — An OpenPGP USB Token Implementation Niibe Yutaka <gniibe@fsij.org>
GnuPGによる鍵対の生成と管理 | mitome.in
SSH into Google Compute Engine VMs with OpenPGP USB token/SmartCard – Matěj Laitl a.k.a. strohel – Technical Blog
PGP Portable USB - YouTube
YubiKeyのOpenPGP機能でリモートホストにSSHログインするまで
GitHub - solokeys/openpgp: OpenPGP functionality for Solo
TurtleAuth: Let's Make a DIY GPG USB Key - Hackster.io
Using an OpenPGP Smartcard with GnuPG
Yubikey の購入ガイド | Ouvill のブログ
YubiKey NEO OpenPGP SmartCard modes
GitHub - ronaldvdmeer/yubikey-openpgp-macos-catalina: This tutorial describes how to set up your Yubikey with macOS Catalina, generate the keys securely and make it work with your SSH client.