Self plug, but here's a PAM module I made for using gpg for login: https://gitlab.com/rendaw/pamgpgr https://gitlab.com/rendaw/pamgpgr . I've been using it for

Self plug, but here's a PAM module I made for using gpg for login: https://gitlab.com/rendaw/pamgpgr https://gitlab.com/rendaw/pamgpgr . I've been using it for a couple years for sudo I think (yubikey). The code is fairly small so it can be an example for doing other PAM things too.