CAPTCHA
CAPTCHA is the Acronym for Completely Automated Public Turing test to tell Computers and Humans Apart
A challenge-response test to verify a user is human, CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) deters bot attacks and spam. The term was coined in 2003 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford. CAPTCHAs are designed to prevent automated software (bots) from performing actions that degrade a given system's service quality, such as submitting forms on websites, creating accounts, or spamming.
Common CAPTCHA Types
CAPTCHAs require users to perform tasks that are easy for humans but challenging for computers. These tasks can include deciphering distorted text, recognizing objects in images, or solving simple mathematical problems.
- Distorted text: Users must enter a sequence of letters or numbers from a distorted image.
- Image recognition: Users must identify objects in images, such as selecting all squares with traffic lights.
- Mathematical problems: Users must solve simple math problems, such as adding two numbers.
Popular CAPTCHA Services
Two widely used CAPTCHA services are Google's reCAPTCHA and Intuition Machines' hCaptcha. Cloudflare, a major website security service, also integrates CAPTCHA to protect websites from abuse and spam.
- Google's reCAPTCHA: Offers various versions, including reCAPTCHA v1, which uses distorted text, and reCAPTCHA v2, which uses image recognition.
- Intuition Machines' hCaptcha: Focuses on privacy and uses image recognition tasks.
- Cloudflare: Integrates CAPTCHA to enhance website security and prevent automated attacks.
