CAPTCHA
Prove you're human
CAPTCHA is an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart—a security measure used on websites to verify that a user is human rather than an automated bot.
Early versions required users to decipher distorted text; modern ones often ask users to identify objects in images or simply click a checkbox.
I had to solve three CAPTCHAs before the site let me create an account.
Identity confirmation through prompted reply
- distorted textMisshapen written characters
- image recognitionIdentifying contents of photos
- checkboxToggleable selection indicator
- puzzleChallenge testing ingenuity
tick box · character recognition · code entry · validation · proof · confirmation · form submission · access gate
Software blocking unwanted email
- web scrapingAutomated site data extraction
- brute forcePower over technique
- credential stuffingAutomated stolen login testing
- click fraudFake engagement for profit
Ease of approach
- frustrationDispleasure from blocked efforts
- illegibleCannot be read
- distortionTwisting from original state
- retryAttempt something again
timeout · visual impairment · user experience · readability · difficulty · failure rate · mobile-friendly · error rate
Confirming genuine identity
- access controlRestricting resource availability selectively
- fraud preventionStopping dishonest financial activity
- identity verificationConfirming someone's claimed self
- online securityProtection for internet activity
Machines mimicking human thought
- human behaviorPeople's actions and reactions
- pattern recognitionIdentifying regularities in inputs
Conveyed through writing
- image-basedRelying on pictures
- behavioral analysisStudy of conduct patterns
challenge-response
Identity confirmation through prompted reply
- distorted textMisshapen written characters
- image recognitionIdentifying contents of photos
- checkboxToggleable selection indicator
puzzle · tick box · character recognition · code entry · validation · proof · confirmation · form submission · access gate · screening
spam filter
Software blocking unwanted email
- web scrapingAutomated site data extraction
- brute forcePower over technique
- credential stuffingAutomated stolen login testing
accessibility
Ease of approach
- frustrationDispleasure from blocked efforts
- illegibleCannot be read
- distortionTwisting from original state
retry · timeout · visual impairment · user experience · readability · difficulty · failure rate · mobile-friendly · error rate · cognitive load
authentication
Confirming genuine identity
- access controlRestricting resource availability selectively
- fraud preventionStopping dishonest financial activity
- identity verificationConfirming someone's claimed self
artificial intelligence
Machines mimicking human thought
- human behaviorPeople's actions and reactions
- pattern recognitionIdentifying regularities in inputs
text-based
Conveyed through writing
- image-basedRelying on pictures
- behavioral analysisStudy of conduct patterns
- Digital SecuritySSL certificate, digital signature, public key, private key, encryption key
- email securityspam folder, spam, spam filters, email filter, encryption
- verificationverification, validation, authentication, certification, proof
- bot defensehoneypot, Cloudflare
- securitysecurity guard, security cameras, alarm system, security system, lock
- checkscheck, personal check, double check, bank check, double-check
CAPTCHAbot
Automated software agent
crawler · spam bot · robot · computer program · automation