CAPTCHA ↔ Challenge-Response test to Auth human intelligence

aka CAPTCHA, Completely-Automated-Public-Turing-Test-to-tell-Computers-Humans-Apart

reCAPTCHA

Google Online API for CAPTCHA. v2.0

Source: www.google.com/recaptcha/about/

Turing Test

Test to distinguish human intelligence (from machine)

References

1. reCAPTCHA ↔ Google Online API for CAPTCHA. v2.0

2. moat ↔ tool to request Bridge from Bridge Authority with CAPTCHA verify