Unfortunately this plugin is no longer bot secure
Here are some bot/spam registrations
Username: AnneHuotelc E-mail: cravenpodium524vq51()outlook.com
Username: Manuela38Y E-mail: cervantesbshr6qi()hotmail.com
Username: RomeoSXZEvz E-mail: rusticjug784w755()outlook.com
Username: LaylaJenks E-mail: undesirablefathfp533()outlook.com
Username: SelmaRickett E-mail: tearfuldoctrine8l687()outlook.com
Two to three registrations each day. I now have converted to a captcha using slightly distorted pictures all spam registrations have stopped.
For this plugin to remain useful, the text need to be replaced by pictures.
I can no longer recommend this plugin