http://qezqo7c2mvdk2ml2ys626hlh7ezva75wwwoawcuc7xncp37kedumv2ad.onion/index.php/CAPTCHA
Lillibridge, Martín Abadi , Krishna Bharat , and Andrei Broder , who used CAPTCHAs in 1997 at AltaVista to prevent bots from adding URLs to their web search engine . Looking for a way to make their images resistant to OCR attack, the team looked at the manual of their Brother scanner , which had recommendations for improving OCR's results (similar typefaces, plain backgrounds, etc.).