Generate an authentication subkey for a private key in your GnuPG
keyring. KEYID is the key ID for the primary key for which the subkey
with "authentication" capability will be generated. If no key ID is
specified, but only one key exists in the secret keyring, that key
will be used. The length of the generated key can be specified with
Generate an authentication subkey for a private key in your GnuPG
keyring. KEYID is the key ID for the primary key for which the subkey
with "authentication" capability will be generated. If no key ID is
specified, but only one key exists in the secret keyring, that key
will be used. The length of the generated key can be specified with