Challenge-response test used to determine whether a user is human (7)
I believe the answer is:
captcha
(Another definition for captcha that I've seen is " E-security feature".)
I've seen this clue in The Guardian.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free.
Check out my app
or
learn more
about the Crossword Genius project.