What is Captcha?
The internet has been an inseparable part of our daily life, with facilities of many web services such as email and search engines. However, these are often attacked by threats from computer programs called bots. To solve this problem, CAPTCHA (Completely Automated Public Turing Test to Tell Computers and Humans Apart) was developed in order to differentiate between computer programs and human users. In addition, this mechanism provides great security and also enables limit automatic registration to web services. Some CAPTCHAs have various weaknesses that allow hackers to penetrate the mechanism of the CAPTCHA. This paper also examines the recent research on various its methods and their categories.
Definition of CAPTCHA
“A CAPTCHA can be defined as one of the challenging web programs which help to protect our websites against threats by generating certain tests that humans can easily pass but computer programs cannot. For example, humans can read the distorted text but current computers cannot”.
Applications of CAPTCHA
- Preventing Comment Spam in Blogs
- Protecting Website Registration
- Protecting Email Address From Scrapers
- Online Polls
- Preventing Dictionary Attacks
- Search Engine Bots
- Worms and Spam
- Advancing Artificial Intelligence
A CAPTCHA refers to an automatically generating new challenges which:
- Current software is unable to solve accurately.
- Most humans can solve
- I didn’t know the type of its if it is new to the attacker.
- CAPTCHAs solve difficult problems in artificial intelligence.
- In 1996, Moni Noar suggested the use of an Automated Turing Test in order to differentiate between human users and bots.
- In 1997 Andrei Broder et al. developed a mechanism to distinguish between human users and computer programs and also in the same year, the Altavista website used this method to block bot programs from entering by displaying a distorted English word to the user and asking the user to copy it.
- In 2000, the term CAPTCHA was given by Manuel Blum and Luis von Ahn at Carnegie Mellon University.
- In 2004, the Yahoo website introduced a version of the EZ-Gimpy method.
Why does Google use CAPTCHA?
Google uses a CAPTCHA to increase the strength of the security around the most sensitive account access points. You may see a CAPTCHA when you:
- When you sign up for a new Google service such as Gmail, Blogger, YouTube, etc.
- Whenever you sign up for any edition of a GSuite Account
- When you change a password on an existing account
- Setting up Google services for a third party device (such as iPhone, Outlook, ActiveSync, etc.)
Why Your Site Needs a Captcha?
For different reasons, there are a lot of people who want to damage your website. They are basically made in use for the purpose of advertising, for fun or for unfair competition.
Captcha helps in preventing robots from manipulating services. Some of the main benefits are:-
1.Preventing fake registrations
It helps to avoid the fake form fill up registrations to sign up. This will damage email campaigns. Some of the social media websites need to register with your emails and passwords. Captcha helps in preventing robots from manipulating services. Some of the main benefits are:-
2.Preventing spam comments
These malicious comments written by some spammers which are not related to your post might irritate the readers and put your site in danger. It helps you to avoid this by enabling only human beings to post comments on the website.
3.Making online shopping more secure
Fraud orders are the main problems that every online store suffers. Competitors used to use invalid names, emails, shipping addresses to order your products; as a result, you will waste time and money to deliver products to no one.
4.Protecting email accounts
It protects the Gmail accounts from the hackers who continuously tries to log in to steal the details.
How Does Captcha Work?
CAPTCHA distinguishes between human and computer programs. It is tough for computers to deal with, but easy for humans to answer.
Humans can see characters from various patterns and shapes, segment a character from the other character overlapping, and know about the characters in their proper context, which a machine finds hard to perform simultaneously.
What is reCAPTCHA?
reCAPTCHA is one of the free services which Google offers as a replacement for the use of traditional CAPTCHAs. reCAPTCHA technology has been developed by the researchers at Carnegie Mellon University, then owned by Google in 2009.
reCAPTCHA is much more advanced in comparison to the typical CAPTCHA tests. Like CAPTCHA, some reCAPTCHAs also asks users to enter images of text that computers feel difficulties.
Over time, Google has extended the features of reCAPTCHA tests so that they no longer have to believe in the old style of introducing blurry or distorted text. Other types of reCAPTCHA tests include:
- Image recognition
- General user behavior assessment
What Are the Different Types of Captchas?
1. Simple math problem
You can see this type of captcha on a regular basis. It has a math problem, which you have to solve and enter the answer. The questions which are very simple, for example, “1+2”, “8-3” can be difficult for a robot to solve.
2. Word problem
This is a well-known type of captcha that varies in different forms but they are divided into two simple parts: a text box and a sequence of letters or numbers. We have to prove your human identity.
3. Social media sign in
When you initiate signing up to a website, enter your private information by using your social account. Instead of asking users to create their own usernames and passwords, the web owner can lead them to use a Gmail or Facebook account with a few simple clicks. The main drawback is that some users may hesitate to link their social sites with a totally new site, which could be off-putting.
This is a more effective type of captcha. We have to spend more time completing the form fill up.
Bots require less time to fill out the form but humans require a bit of time more to enter the required information. Users can easily get irritated when wasting time, filling out many forms every time.
Honeypot considers hidden fields on the web page in order to trick bots. Bots will fill out all fields they find, even the invisible ones. Whenever bots fill it out, then the website can instantly see and decide that it is not a true human user.
Users are not disturbed by any annoying captcha games or spending time inputting lots of unnecessary information.
6. Picture identification
Picture identification captcha refers to different forms of image test, from naming images, differentiating images from a set of images to choose an odd image from the set. This type of captcha takes full advantage of the bots’ weaknesses in vision in order to solve image-related problems.
7. No captcha Recaptcha
This type of captcha has been launched since 2014 but it has become increasingly well known on the internet. It displays “I’m not a robot” with a checkbox that you have to click on.
This method tracks the movement and figures.
8. Invisible Recaptcha
Invisible Recaptcha is the newly updated version of No captcha Recaptcha. This captcha is invisible to the users, which helps the user to work easily. Therefore, the users don’t need to check the box, enter the text, match the images or fill out the form.
9. Confident Recaptcha
Confident captcha is an image-based method which provides a selection of images as per the instructions. Website makers can earn and use this captcha advertising, to earn revenue.
Confident Recaptcha has a success rate of more than 96 %, but the users can’t do the task correctly for the first time and have to try again and again with a different image, which can make them discouraged.
10. Sweet captcha
A sweet captcha is an effective tool in order to determine identity. It may disturb the user while working since it might take time to complete the challenge.
The smart devices have fingerprint sensors that are used to confirm an unmatched identity. It provides complete security from captcha.
Everyone has different fingerprints, so it makes simpler to prevent bots from spamming websites.
Few advantages of Captcha are:
- Increases security
- Reduces spams
- Blocks automated increased usage of services
- Makes online activity safer
- Differentiates human and computers
Few disadvantages of Captcha are:
- Fails in certain browsers
- At times is difficult to read
- Challenging for people with certain disabilities
- Not guaranteed to be full-proof
Captchas Still Have Some Drawbacks
We should be aware of its drawbacks. The disadvantages of captcha include:
We must imagine whenever you open a website, it takes you some time to perform in order to verify humanity. There are also some impatient people who might lockout and find an alternative website when they have to pass with various online tests.
Inaccessibility is another problem
The captcha is developed under much more complicated challenges, making it more complex for those who have some kinds of eye dysfunctionalities.
Not an effective remedy against bots
You may believe that captcha will protect your website from threats otherwise, it is not always perfect. Nowadays, advanced bots have initiated bypassing captchas, so it turns out that captcha actually leads to blocking basic bots from threatening your site.
Some Important Questions to Discuss
What is the best Captcha to use?
Here are 8 CAPTCHA Alternatives for Better UX
PlayThru. Get on the verified human whitelist
- Biometric Security
- Text Message Verification
- The Honeypot Method
- Math Captcha
- Confident Captcha
- No CAPTCHA from reCAPTCHA.
2. Is Captcha typing a job legal?
There is no law made to describe which considers CAPTCHA typing to be illegal. CAPTCHA typing jobs are helping hands of spammers and frauds to continue their illegal activities. So, although it’s not illegal, CAPTCHA typing is an unethical way to make money online.
3. How do I stop reCAPTCHA?
If we want to disable reCAPTCHA, just go to your dashboard, and click on the settings toggle bar. Then you must toggle the “reCAPTCHA” setting in order to enable or disable it.
4. How does Captcha verification work?
The full form of CAPTCHA is a Completely Automated Public Turing Test to distinguish Computers and Humans Apart. Its main objective is to identify if a user (of an app or a website) is a real person or a bot. It believes in specific traits that people can understand and machines don’t.
5. How do you earn in Captcha typing?
Here are these 8 sites below, join them one by one & start solving the Captchas and you can easily earn from these apps.
- images typed
6. What is the difference between Captcha and reCAPTCHA?
It is the human validation test used by many sites to prevent spam. reCAPTCHA is the reversed form of CAPTCHA – this is also the same as the human validation test used not only to prevent spam but also to serve in the book digitization project.