extra security for signup on coursepress pro

Hi There,

I installed coursepress pro and am trying to get added security/ verification added to the signup forum. My site is constantly under attack with spam and i am afraid without the ability to add a verification e.g. simple sum of question i will put my site under a huge risk for thousands of robot signups within an evening.

Please can you advice on this and explain as to how i could get this done?

Thank you so much!

Kind Regards