quick link to recent captcha guidelines?

Hi all,
I am currently involved in a discussion on the Google accessibility list 
regarding the use of math problems as a form of captcha.  the individual 
is stating that such a substitution carries no security whatsoever.
Given the places where I have personally, and thankfully  found the math 
problem  verification present,  I am wanting to share the recent w3c 
information on their use.
Can anyone give me a simple link to  a relevant section, or share an 
article discussing math problems as captcha challenges with their  pros / 
cons?
Thanks,
Karen

Received on Monday, 9 September 2019 21:11:53 UTC