ChessCaptcha.
This is a captcha system where the user either recreates the position of the pieces on the board - non chess savvy users - or she solves a mate-in-one puzzle by putting the piece on the square where it gives the checkmate - chess savvy users only. There is also a no-js fallback...
#1 super security anti-spam captcha plugin for WordPress forms
Captcha plugin is the best security solution that protects your WordPress website forms from spam entries. It can be used for login, registration, password recovery, comments forms and much more.
It is easy to use and manage, a...