September 22, 2020
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What is captcha?  


What is Captcha?
If you use the internet regularly on computers, regularly surfing the web, you will surely be afraid of captcha entries, or at least heard the concept of "Captcha". So what is captcha?

CAPTCHA is a type of verification test used in computers to determine if a user is a real human. The CAPTCHA is the first string of abbreviations for Completely Automated Public Turing test to tell Computers and Humans Apart, which translates as "Fully automated public Turing test to distinguish computers from people". Was once tried by Carnegie Mellon University to apply for copyright but it was rejected. CAPTCHA is the process by which a server requires the user to complete a simple test that the computer can deexdangf create in itself that the computer itself cannot solve. Therefore, only authorized users can complete the CAPTCHA.
The term captcha was introduced by Luis von Ahn, Manuel Blum, Nicholas J. Hopper (all of Carnegie Mellon University), and John Langford (then of IBM) in 2000. A common type of CAPTCHA is usually a series fuzzy numbers, distorted characters, etc. require all users to match the range of characters in the image.
A CAPTCHA sometimes acts as a Reverse Turning test, because it is created by a machine and targeted at a human object. And the standard test is that humans create and aim for new hooks.
Features of Captcha
- The current computer can not solve CAPTCHA correctly.
- Most people can solve it.
- Regardless of whether the CAPTCHA type is new to the attacker. Although a "click here if you are not a computer" checkbox can be used to distinguish between people and computers, it is not a CAPTCHA because it depends on the fact that an attacker does not have to spend too much effort to break the form like that.
How does CAPTCHA work?
The purpose of this display is to distinguish and identify exactly who you are, not malicious software, malware programmed to log in to break the system. For weak malware or weak illegal access, it is often stopped at the CAPTCHA validation step because it cannot understand or recognize images.

CAPTCHA is also used by technology giants like Google (in the form of "I am not a robot") to prevent automated virtual clicks from machines and robots to increase the amount of real interaction. According to the latest statistics, if we humans type the CAPTCHA code in the request box, the probability is 80% (some CAPTCHA exceptions are too hard to read that will cause the user to retype the 2.3 times), and The ability of machines not properly programmed to penetrate, the probability of its success is only 0.1%. CAPTCHA is also a form of security for data ports, information on your website.
So, it can be said that CAPTCHA validation is also a form of security for data portals and information on your website. The modern CAPTCHA also helps to maximize the automatic blocking of computers and robots, while minimizing the processes and difficulties experienced by users.
Why should websites use CAPTCHA?
With its advantages, CAPTCHA is increasingly used in security systems, especially for channels that own large databases that need to be protected as websites, CAPTCHA appears as an essential element. Here are some of the reasons and benefits that CAPTCHA can bring to your website.
Ensure the amount of real interaction: In the website, interaction with users is the key and also an important goal that many businesses target. But what if your customers are just machines or automated robots? These illegal access are not beneficial to your site, but they also consume bandwidth and web capacity. Therefore, CAPTCHA is a lifeline for you to make sure that the people who access the important content on your website are real people - your potential customers. Make sure the audience accessing the important content on your website is real
Ensuring security and confidentiality: We will not know what the automatic access systems or the robots after accessing the website will do next, some types of robots are "benign", non-toxic but Besides, there are also many harmful elements that bring high risks to the website. So using CAPTCHA is a way to prevent this from happening.

Against spam, create an account automatically or make self-posting in forums, websites: Many web developers, web designers as well as forum managers have had a lot of headaches before the status of spam, made posting or bulk account spamming. And using CAPTCHA can help them avoid this. The new type of Google CAPTCHA requires users to identify with images
Application of CAPTCHA

Captcha is used to prevent software from automatically performing tasks that degrade the service quality of an existing system.
Captcha can be used to protect the system against spam e-mail actions.
Captcha is also used to prevent automatic postings in blogs and forums. Fight against systematic anti-system action.
Why do CAPTCHA look so hard to read?
If the CAPTCHA is too easy to read so it only takes you 1-2 seconds to read, so does the computer program. The computer program can scan that CAPTCHA sample and look it up in the character table and return the results. This will lead to the system being compromised by hacker computer programs, spammer. Therefore, the CAPTCHA must be distorted and distorted, so that only the human eye can analyze it.
Do you think CAPTCHA is easy to bypass?
The answer would be no, but that's just for general spammers. As for professional developers or hackers, they will find an algorithm that can easily crack a CAPTCHA string. However, not everyone can do it.
What is the modified version of CAPTCHA?
The use of "traditional" CAPTCHA, which means typing a set of characters or phrases to distinguish between a computer and a real person, is increasingly being "bypassed" by spammers, hackers and professional software, or hire a team to sit down and type CAPTCHA. Therefore, a new form of CAPTCHA was created, called no-CAPTCHA.
Instead of typing CAPTCHA like before, now, when you create a Gmail nick, you just have to press the "I'm not a robot" button. Why is that so simple? That's because Google has used the no-CAPTCHA algorithm, a system that tracks users' behaviors and then filters out which computers are human.
If in doubt, no-CAPTCHA will use an image recognition tool, which requires you to select an image that is identical to the data the system issues to verify human accuracy again. Thereby you can easily bypass CAPTCHA but the system is still safe from automated computers created by hackers.
Google's reCAPTCHA
reCAPTCHA is a check box with the content: I'm not a robot (I'm not a Robot) and users click on it to verify. Sometimes clicking on it is ok but sometimes you have to answer one or more questions about image selection verification.

ReCAPTCHA (solution) verified successfully.

Must select images to solve Captcha.
The solution to reCAPTCHA is to select some of the image boxes in some areas according to the question such as: select the image boxes as traffic signs, select the images with cars until there are no more pictures, select the images with path, ... Sometimes you get stuck on a lot of steps.
Google's reCAPTCHA also has an intelligent algorithm that you can just check into a non-robot box because the algorithm knows that the click is coming from a user, sitting in front of a real computer.
Google uses reCAPTCHA in most of its operations. You can integrate reCAPTCHA onto your website for free.
To solve the reCAPTCHA completely automatically, there is probably no system that can do it but there is an online reCAPTCHA translation service: meaning you meet the reCAPTCHA and you will send the image to the server of that service, that service has a lot of real people always look at the solution picture and send the results of the selected squares to you ... This solution is popular and must be paid for the number of times to solve.



This topic was modified 6 months ago by Coin news web