Anti-Spam for Submissions

DirectoryPress v7.14
WordPress 3.6

Is there a better solution for controlling spam submissions than requiring a login?

Once I began requiring a login and a Captcha, my spam submissions have dropped to zero. However, due to constant attacks on WordPress-based sites, my web hosting company (WebHosting Hub) blocks logins to WordPress-based sites nearly all the time.

Of course, I can get in by excluding my IP number in .htaccess but if no one can login to my directory, they can’t submit a site.

Is there a way to require a Captcha in order to submit a site listing to the directory, without requiring a login?

I can handle spam submissions from human beings but, unless I require a login, I have hundreds of them every hour, which suggests that they are automated.

Also, as an unrelated question, I have noticed that on the PremiumPress Community Forum, no mention is made of DirectoryPress any longer; rather, it is referred to as Directory Theme. Is DirectoryPress being discontinued or otherwise deprecated?