This plugin's installation page says,
If you would like connections to your admin panel to be secure, enable Force SSL Admin. If you are using a non-default SSL Host, do not use WordPress' built-in FORCE_SSL_ADMIN or FORCE_SSL_LOGIN.
If I'm not supposed to use FORCE_SSL_LOGIN with shared SSL, what's the best way to enable SSL logins? I don't need to secure my entire admin panel (FORCE_SSL_ADMIN); I just want login credentials encrypted.