Captcha – a fully automated open Turing test to distinguish between computers and people; a test used to determine whether a user of a computer system is a human or a computer. Developed at Carnegie Mellon University in 2000. The main idea of the test is to offer the user a problem that is very simple for a person and very difficult for a computer. The purpose of the test is to protect the Internet resources and its users from spam, floods or other undesirable intrusions.
The most common CAPTCHA version includes user-defined characters (often those characters are distorted or translucent). According to generally accepted norms, even for the visually impaired, a speech recognition option should be added to the CAPTCHA. Other difficult algorithmic tasks can also be applied: for example, to know what is in the picture, to mark all the pictures of the cat, and so on. However, the standard is the recognition of characters, because it is not related to any culture and works in mobile browsers.
I am Magas 