yubikey SSH simple guide for SSH resident keys

gistfile1.txt

# To generate:

```
ssh-keygen -t ed25519-sk -O resident -O verify-required -C "0000000" -O application=ssh:0000000 -f $HOME/.ssh/id_ed25519_sk_000000
```

The `-O application=ssh:0000000` ensures that it will import and save with that name when you run `ssh-keygen -K`, preventing overrides.

And if you move computers, in the new one just run

```
ssh-keygen -K
```

which will load the secret key ID (not the actual secret key) from the yubikey and place on the .ssh folder.

# To use:

```
sudo apt install -y gnupg2 gnupg-agent scdaemon pcscd yubikey-manager
```

```
gpg --card-status
```

Add this to your shell profile (~/.bashrc, ~/.zshrc, etc.):

```
export GPG_TTY=$(tty)
export SSH_AUTH_SOCK=$(gpgconf --list-dirs agent-ssh-socket)
gpgconf --launch gpg-agent
```

Then reload your shell or run:

```
source ~/.bashrc  # or ~/.zshrc
```