ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

What is CAPTCHA and why it is used?

Updated on March 6, 2013

Where have you seen CAPTCHA

We all are familiar with CAPTCHA.Even a normal Internet user have come across many CAPTCHAs.Most websites like Yahoo,Microsoft any many others use this program as a part of new users Sign up and in many more sites where we post comments,order products and many more.In all these cases we come across a distorted text between images where we are supposed to type those text.Unless we read those text and type in correctly,we are not allowed to proceed.Sometimes,the text may be too much distorted that you can't read at all.Once you type it wrong,you have to come up again with another distorted text.Feel fed up with those?Why all these useless?Have you ever thought?It is true that we all spent a few seconds to read and type those text correctly.But the fact behind this is that it's a way to ensure that a human is using the interface and not any Computer programs.

What is CAPTCHA?

CAPTCHA is program, that generates tests like asking user to read distorted text and type in a specific area.It stands for Completely Automated Public Turing Test To Tell Computers and Humans Apart .It was developed in Carnegie Mellon University to be used by Yahoo.


CAPTCHA in Google

CAPTCHA in facebook

CAPTCHA for Internet Security

Preventing bogus comments

You might have come across bogus comments in blogs.These are comments which make no sense,just jumbling up of letters and is posted by an unknown user.An example is shown below.

Author : zsruspgzgtw (IP: 204.147.87.98 , horton.iaces.com)

E-mail : dydpsf@ncebra.com

URL : http://rlzjxjayrzmo.com/

Whois : http://ws.arin.net/cgi-bin/whois.pl?queryinput=204.147.87.98

Comment:

iszwUT zlaqlsxekynz, [url=http://ddklkpdrneog.com/]ddklkpdrneog[/url], [link=http://nxzhyytqnuwe.com/]nxzhyytqnuwe[/link], http://khfpeoiqwwtp.com/.

Using CAPTCHA for posting comments ensures that a human user is posting comments.Also,the user need not sign up for posting comments.Just entering the CAPTCHA text correctly ensures that a human user is posting the comment.

Preventing bots in Website Registration

There are may websites that allow free sign up.'Bots' are a kind of attack that signs up in many such websites.Using CAPTCHA in such cases can ensure that only human users sign up and create accounts.

Dictionary attacks in password systems

Dictionary attack is a kind of password hacking by entering all the words in dictionary as password.Spammers often use this kind of attack.Asking user to solve CAPTCHA after certain number of password entries prevents this kind of attack.

Protection against worms and spam

Using CAPTCHA does not accept any mails or comments from users other than humans.In this way it provides protection from worms and spam.

Preventing abuse in online polls

Using CAPTCHA in online polls prevents spam voters.Solving CAPTCHA here ensures that only humans cast votes.This also makes such voting contests trustworthy.

Use CAPTCHA in your site

Using CAPTCHA in your site can help you to avoid spam and makes your site secure.You can use the following link to use CAPTCHA in your site:

http://www.google.com/recaptcha

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      Ds 

      4 years ago

      best example for CAPTCHA in google!!rofl....

    • leeba ann varghes profile imageAUTHOR

      Leeba Ann Varghese 

      4 years ago from India

      @Johnf991...sure sure..iam happy as well.

    • profile image

      Johnf991 

      4 years ago

      Id forever want to be update on new articles on this internet site, bookmarked ! . eadcdbdfgkgd

    • profile image

      Johnb457 

      4 years ago

      Do you mind if I quote a few of your posts as long as I provide credit and sources back to your weblog? My blog is in the very same niche as yours and my users would truly benefit from a lot of the information you present here. Please let me know if this alright with you. Thank you! aegkecedcfdg

    • Cogerson profile image

      UltimateMovieRankings 

      6 years ago from Virginia

      I think CAPTCHA is becoming more popular everyday...as I see more and more websites using it...including HubPages when you are sending e-mail...thanks for sharing this information...voted up and useful.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)