Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA)

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Abbreviations / Acronyms / Synonyms:

CAPTCHA

NIST SP 800-63-3

Definitions:

An interactive feature added to web forms to distinguish whether a human or automated agent is using the form. Typically, it requires entering text corresponding to a distorted image or a sound stream.
Sources:
NIST SP 800-63-3

Glossary Comments

Comments about specific definitions should be sent to the authors of the linked Source publication. For NIST publications, an email is usually found within the document.

Comments about the glossary's presentation and functionality should be sent to secglossary@nist.gov.

See NISTIR 7298 Rev. 3 for additional details.