“The conclusion can be extended that the true purpose of reCAPTCHA v2 is a free image-labeling labor and tracking cookie farm for advertising and data profit masquerading as a security service,” the paper declares.
Google’s rebuttal (NB: The hyperlinks send you directly to Google domains):
In a statement provided to The Register after this story was filed, a Google spokesperson said: “reCAPTCHA user data is not used for any other purpose than to improve the reCAPTCHA service, which the terms of service make clear. Further, a majority of our user base have moved to reCAPTCHA v3, which improves fraud detection with invisible scoring. Even if a site were still on the previous generation of the product, reCAPTCHA v2 visual challenge images are all pre-labeled and user input plays no role in image labeling.”
We explore the cost and security of reCAPTCHAv2 and conclude that it has an immense cost and no security. Overall, we believe that this study’s results prompt a natural conclusion: reCAPTCHAv2 and similar reCAPTCHA technology should be deprecated.
edit: I just realized, my links are about the very same study, that also The Register refers to… just a different quote…
One of the versions of Captcha had lots of photos of house nunbers that you had to type in. Oddly enough, after that had been running some time, house numbers started to appear for the first time on Google Maps and became searchable in Street View.
No doubt Google will insist that that was the merest coincidence. I call BS on that.
Or perhaps Google will confess to doing this in the past and say it has stopped by v3. If they freely admit to past wrongdoing I would be slightly more inclined to believe them about the future.
Another indicator that their secondary purpose may be for training the “machine:”
If you’ve ever used reCAPTCHA’s audio-mode, you may have noticed that the audio clips usually contain garbled, very difficult to understand vocal samples - so hard to decipher that you sometimes give up and try a different sample, or even revert to the visual reCAPTCHA to spend several minutes clicking fire hydrants, buses, crosswalks, motorcycles, or whatever.
The vocal samples usually sound like excerpts from a presentation given by some lecturer, or a reading of some sort. It seems as though Google is crowdsourcing speech-to-text transliteration.
In any case, I’ve found that it’s often sufficient to supply the one or two words from a sample that are easy to understand, and ignore the most garbled parts, in order to get past the gatekeeping.