Facts about CAPTCHAs and reCAPTCHAs

Today this blog will be about some common facts about CAPTCHAs.

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What is a Captcha?

• According to  Wikipedia , Captcha is abbreviated to "Completely Automated Public Turing test to tell Computers and Humans Apart" 

Basic functions of a captcha is to felicitate to make sure that a website user is actually human, because computers had (and to an extent, are still having) a tough time reading text like that.

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Now majority of people will be wondering - "Why to waste so much human effort to solve a naive CAPTCHA ?"

Answer to such question can be easily speculated that in old days(when COMPUTERS and INTERNET was limited to mere group of people) , humans(particularly HACKERS and CRYPTOGRAPHERS),wanted to maximize the understanding of computers by giving computers hard time.

Credits- WIKIPEDIA

--They would replace a word with look-alike characters. HELLO could become |-|3|_|_() or )-(3££0, as well as numerous other variants, such that a filter could not possibly detect all of them.

  
At first glance they can be assumed as EMOTICON. (An emoticon is a pictorial representation of a facial expression using characters—usually punctuation marks, numbers, and letters—to express a person's feelings or mood, or as a time-saving method.) 

Doesn't it seem ironical literally they are like EMOTICONS and time saving.

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-People are here misled to believe that captchas are only for security .

-ACTUALLY they were first meant to be for securing human interaction with malicious websites .

Now I will discuss the real use of "CAPTCHA" and "reCAPTCHA"

Chances are that you will be confused between  "CAPTCHA" and "reCAPTCHA". The basic difference between them is on the basis of how they are used in internet community.

reCAPTCHAS as in WIKIPEDIA   "is a CAPTCHA-like system designed to establish that a computer user is human (normally in order to protect websites from bots) and, at the same time, assist in the digitization of books".

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While surfing internet and jumping through many websites , you may have encountered embedded dialog box like this

This is a typical example of a reCAPTCHA used in websites.

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And the most interesting reCAPTCHAS (my favourite ones)

 This reCAPTCHAS has its significance .
Can you see the quote on the CAPTCHA on right-bottom side quoting -

"STOP SPAM READ BOOKS"

Here lies the beauty of reCAPTCHA . 

You may have noticed that above, you had to type two words instead of just one.

Here, one word is used to genuinely check if you’re human. And the other word is from a scanned copy of an old book and is showed to you to basically ask you to digitize it.

Google then acquired it in 2009. And guess what? ReCaptcha was used (mainly on pages that couldn’t be scanned properly) to digitize all books on Google Books, to make them searchable.

“reCAPTCHA offers more than just spam protection. Every time our CAPTCHAs are solved, that human effort helps digitize text, annotate images, and build machine learning datasets. This in turn helps preserve books, improve maps, and solve hard AI problems.”

Source: Easy on Humans, Hard on Bots

END OF BLOG

Hope you liked the blog and do share with your peers.
I tried my best to give a quick picture of CAPTCHAs. 

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SOURCE- WIKIPEDIA.
HELP from QUORANs.