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Have a look at the image below:

Are you squinting and trying to hard to figure what is written in the phrase below?

This was the ‘Captcha’ phrase that was used to differentiate between ‘humans’ and ‘bots’. This has been slowly replaced by the new ‘reCaptcha’. Before we get into the details of the ‘reCaptcha’ let us discuss ‘Captcha’ and what it was meant for.

History of ‘Captcha’ and the necessity for it:

‘Captcha’ is ‘Completely Automated Public Turing test to tell Computers and Humans Apart’ and it made its first appearance in 1997. While most of us may expect only human usage on websites, there are spammers and other malicious programs(also known as ‘bots’) that are constantly bombarding websites with their evil intent. The ‘Captcha’ phrase was specifically created to differentiate between these ‘bots’ and genuine human users. Though the concept of ‘Captcha’ itself was invented in 1997, the term was first created by  Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford in 2003.

What exactly are “bots” now?

There are good chances that you would have encountered a “bot” but did not realize that it was truly one.”Bots” in simple terms have been created to perform automated tasks. There are plenty of good “bots” that perform automated tasks like chatting (“chat bots”) , handling customer requests, scheduling meetings. Facebook Messenger, Microsoft Skype all rely on “bots” to power and improve their communication and user experience.

The malicious “bots” on the other hand spam websites, steal email addresses and make use of them on other portals. The malicious activities by “bad bots” are carried out for personal and financial purposes. Captcha was designed to block these “malicious bots”.


Different types of ‘Captchas’ are present to circumvent bots. Some of them are listed below:

  1. Text based Captcha: The first and most common type of ‘Captcha’ is the text made Captcha. It is made up of phrases and text in a convoluted manner that make the the ordinary human squint and perspire to decipher them! But it is one of the popular ‘Captchas’. Like with other aspects of security, the text based ‘Captcha’ phrases found their nemesis in OCR or ‘Optical Character Recognition’. OCRs were used by bots who used them to crack the ‘Captcha’s and this type of Captcha was easily compromised by “bots”.
  2. Mathematical Captcha: Mathematical Captchas are slightly simpler than their text based counterparts. They will instruct you to solve a simple mathematical equation to prove that you are human.
  3. Image based Captcha: Image based Captchas instruct you to pick all images conforming to a certain rule(for example, “Pick all buildings that have a door”)to prove you are human.

The main disadvantages when using Captchas are that certain bots do get through and they are an annoyance to the user.


Amidst all the security concerns of ‘Captcha'(as bots are getting through), Google launched the “No Captcha reCaptcha’ in 2014 which promised enhanced security and ease of use for websites. The new reCaptcha makes use of an advanced risk analysis engine. The new reCaptcha API lets legitimate users of websites easily pass through without them having to squint and decipher hard phrases.It does not have the traditional and annoying hard to read phrases to prove that you are human.  This is how the “reCaptcha” looks like:

In this type of “reCaptcha”, users are validated with a “I am not a robot” checkbox(as in the above case) The “check box type reCaptcha” is more user friendly.

reCaptcha updated:

The “reCaptcha” was updated in 2017 and in this second type of “reCaptcha”, users are validated in the background also known as “invisible reCaptcha” (It does this by noting the IP address of the user and analyzing mouse movements) The users can also be validated more(in case there is any doubt of them being a bot) by being presented with the checkbox version of the “reCaptcha”.

The two versions of “reCaptcha” will definitely give “bots” a much more tougher time to enter websites and that might mean more security for us online.

Images source: Google images

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