add Recaptcha to Sign In

Hi everyone:
Thanks for all the support and Vanilla forums in general.
Is there a way to add the Recaptcha to the general sign-in form, not just the create new account (apply for membership) form?
I'm just thinking if there was ever a brute-force attack, someone might be able to hack into an existing username.
Also, and this is off-topic: has anyone ever made an image captcha such as this one https://wordpress.org/plugins/image-captcha/screenshots/ for Wordpress?
Reason I ask, I heard awhile back that google developed a way for computers to read characters. It might be wise for someone to look into this before bots start cracking recaptcha.
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