What Is CAPTCHA? What is CAPTCHA? This is an acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart” it is a challenge response that is normally used in the computing process to determine whether the user is human or not. It is a system that is used to ensure that the user accessing some sites online is a human being and not a robot. With the current advancements in technology, people are using robots to assist them which is not a good idea for most of the internet sites. The CAPTCHA requires the user to type the letters that are presented to him/her in distorted form image. They are obscured sequence of letters that a robot is not in a position to identify. Therefore the only user who that can identify the digits are human being. Thus method of identification has received a lot of criticism from the disabled since they are not in a position to see the images as they are placed on the screen. More criticism comes from those people who think that their work is being slowed down by the distorted words that are sometimes illegible. Effects of CAPTCHAs on User Experience A user will get used to using the internet personally and stops the use of robots. This is because they will be used to the fact that they are not able to access those sites with a robot since CAPTCHA is required. Another effect of this on the user experience is that some people abandon some sites due to CAPTCHA. Sometimes people do not want to waste time refreshing for a clearer image. Some users will give up on certain sites. What are the applications of CAPTCHA? They are applied to prevent bots from collecting some sensitive information or using some restricted computer services. This is mainly to prevent bots from taking part in some of the online activities such as the online polls, signing up for the free e mail accounts that are normally used to send spam and collecting of the e mail addresses. The CAPTCHAs can also prevent bot generated spam as it requires that the user pass the test before the message is delivered. Moreover, they are utilized to prevent people from using bots to assist them download some massive staffs from internet sites and the multimedia websites. Besides, they are used in the online messaging boards and blog comments to prevent the bots from posting spam links. What are the characteristics of CAPTCHA? It is a fully automated system that requires little intervention or human maintenance in administering test. This will reduce the total cost and it is very reliable. The modern CAPTCHAs (text based) are designed such that they require the simultaneous use of three abilities that are separate. The three abilities are segmentation, parsing and the invariant recognition. These are meant to allow the user complete the task completely without any consistency correctly. The CAPTCHAs can be refreshed in case the obscured images are not clear. This is meant to reproduce a different image that is clearer for the user to identify. This is mainly applicable when the user is not in a position to differentiate the lower case and the upper case letters. The Accessibility of the CAPTCHAs They can be accessed either as letters where the user is supposed to identify correctly the letters that are displayed in an obscured manner. When the letters are entered correctly, the user is allowed to access the site he/she was targeting. Another way to access the CAPTCHAs is by use of audio files where you are to hear the voice and identify the letters. You are to feed the digits you hear and if you will identify them correctly, you will access the site. If you’ve asked yourself, ‘What is CAPTCHA’, now you know that it prevents the use of bots to assist human beings or to prevent the spam contents.