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 (kăp′chə) Computers
A security feature, as on a webpage, that attempts to distinguish between legitimate human users and bots by requiring users to perform a mildly challenging task such as deciphering distorted text.

[Acronym of c(ompletely) a(utomated) p(ublic) T(uring test to tell) c(omputers and) h(umans) a(part), coined in 2000 by the researchers who developed the security feature and intended to suggest a colloquial pronunciation of capture.]


(Communications & Information) a test in which the user of a website is asked to decipher a distorted image, used to protect the website against automated attacks
[C21: acronym for C(ompletely) A(utomated) P(ublic Turing Test to) T(ell) C(omputers and) H(umans) A(part)]
References in periodicals archive ?
Solve Media's TYPE-IN(TM) technology creates extremely effective branding opportunities to engage consumers through CAPTCHA, display, video, pre-roll and mobile formats.
Ahn's reCAPTCHA, now owned by Google, uses the CAPTCHA interface to break up digitizing projects into two-word chunks of old scanned texts.
Put simply, CAPTCHAs are automated systems used to distinguish other automated systems from flesh-and-blood ones.
New DNSSEC Security Measure, Along with Existing CAPTCHA, Help Defend Computers from Web Hacking, Phishing and Other Growing Security ThreatsD-Link Middle East & Africa, the end-to-end networking solutions provider for consumers, businesses, and service providers, today announced it is the first in the industry to enhance its router security to a higher level of protection by incorporating both CAPTCHA and DNSSEC to guard against hacking, worms, viruses and other malicious Web attacks.
The on-line process required electors to complete a CAPTCHA challenge, and then use their PIN and date of birth to confirm their identity.
CAPTCHA Request: The Web server submits the request to the CAPTCHA agent.
Logging in to Gogo via BoingoOs easy-to-use one-click app is as simple as accepting the flight segment charge and entering a CAPTCHA validation phrase.
The online voting process prompted electors to complete a CAPTCHA challenge (35) and then use their unique PIN and DOB to verify their identity.
Are You a Human: The answer to frustrating CAPTCHA entries, Are You a Human uses fun games to verify the authenticity of people completing online forms
will detail a new CAPTCHA technique designed to overcome the usability problems of mobile tablet devices such as smartphones, which do not use keyboards.
Featured were demonstrations of a new method for securely downloading keys to RFID devices using mobile phones and a novel CAPTCHA technique that improves human recognition without compromising security.