Google is making changes to its reCaptcha system: distorted text images are out, while numbers and more-adaptive, puzzle-based authentication checks are in. The change is necessary because text-only Captchas are no longer blocking a sufficient number of automated log-in attempts, Google says. The Captcha — an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart — was first developed at Carnegie Mellon University in 2000. In theory, Captcha can be used for a variety of tasks, including preventing automated spam from appearing in blog comments, blocking automated spam-bot signup attempts.”]
Source: https://www.darkreading.com/attacks-breaches/google-captcha-dumps-distorted-text-images