File:Gimpy-r_CAPTCHA.jpg · Wikimedia Commons · See Wikimedia Commons
CAPTCHA
Sign in to saveAlso known as Completely Automated Public Turing test to tell Computers and Humans Apart, CAPTCHA (Challenge-response test)
upright=1.35|thumb|This CAPTCHA (GIMPY-R, c. 2005) of "smwm" obscures its message from computer interpretation by twisting the letters and adding a slight background color gradient.
A CAPTCHA is a test that asks you to prove you're human by completing a task a computer can't easily do, like reading distorted letters or identifying objects in images. Websites use CAPTCHAs to prevent automated programs from accessing accounts or abusing services.
AI-generated from the Wikipedia summary — may contain errors.
~14 min read
Encyclopedic overview
15 sectionsContents
- Purpose
- History
- Characteristics
- Accessibility
- Circumvention
- Machine learning–based attacks
- Human labor
- Outsourcing to paid services
- Insecure implementation
- Alternative CAPTCHAs
- Malicious CAPTCHA imitations
- See also
- References
- Further references
- External links
upright=1.35|thumb|This CAPTCHA (GIMPY-R, c. 2005) of "smwm" obscures its message from computer interpretation by twisting the letters and adding a slight background color gradient.
A CAPTCHA ( ) is a type of challenge–response Turing test used in computing to determine whether the user is human in order to deter bot attacks and spam.
Excerpted from Wikipedia’s “CAPTCHA” article, available under the CC BY-SA 4.0 licence.