Captca
What is CAPTCHA? – Google Workspace Admin Help
Send feedback help content & informationGeneral Help Center experience CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a type of security measure known as challenge-response authentication. CAPTCHA helps protect you from spam and password decryption by asking you to complete a simple test that proves you are human and not a computer trying to break into a password protected account.
A CAPTCHA test is made up of two simple parts: a randomly generated sequence of letters and/or numbers that appear as a distorted image, and a text box. To pass a the test and prove your human identity, simply type the characters you see in the image into the text box.
Why does Google use CAPTCHA?
Google is committed to keeping your information safe and secure. CAPTCHA offers protection from remote digital entry by making sure only a human being with the right password can access your account. CAPTCHA works because computers can create a distorted image and process a response, but they can’t read or solve the problem the way a human must to pass the test.
Many web services, including Google, use CAPTCHA to help prevent unauthorized account entry. You may also see CAPTCHA on other sites that provide access to sensitive information, such as bank or credit card accounts.
When does Google use CAPTCHA?
Google uses CAPTCHA to strengthen the security around the most sensitive account access points. You may see a CAPTCHA when you:
Sign up for a new Google service (Gmail, Blogger, YouTube)
Sign up for any edition of a Google Workspace Account
Change a password on an existing account
Setup Google services for a third party device or application (such as iPhone, Outlook, ActiveSync, etc. )
I am having difficulty viewing a CAPTCHA image. What can I do?
If you can’t see a CAPTCHA image or are having trouble reading the text, refresh your browser for a new image.
Although CAPTCHAs normally rely on images, audio versions are available for the visually impaired. To access an audio version, click the link that appears near the text box as the International Symbol of Access image (the wheel-chair icon). The alternate text for this image is, “Listen and then type the numbers you hear. ” CAPTCHA is not supported for the deaf-blind community.
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What Does CAPTCHA Mean? | CAPTCHA Types & Examples
What is CAPTCHA
CAPTCHA stands for the Completely Automated Public Turing test to tell Computers and Humans Apart. CAPTCHAs are tools you can use to differentiate between real users and automated users, such as bots. CAPTCHAs provide challenges that are difficult for computers to perform but relatively easy for humans. For example, identifying stretched letters or numbers, or clicking in a specific area.
What are CAPTCHAs Used for
CAPTCHAs are used by any website that wishes to restrict usage by bots. Specific uses include:
Maintaining poll accuracy—CAPTCHAs can prevent poll skewing by ensuring that each vote is entered by a human. Although this does not limit the overall number of votes that can be made, it makes the time required for each vote longer, discouraging multiple votes.
Limiting registration for services—services can use CAPTCHAs to prevent bots from spamming registration systems to create fake accounts. Restricting account creation prevents waste of a service’s resources and reduces opportunities for fraud.
Preventing ticket inflation—ticketing systems can use CAPTCHA to limit scalpers from purchasing large numbers of tickets for resale. It can also be used to prevent false registrations to free events.
Preventing false comments—CAPTCHAs can prevent bots from spamming message boards, contact forms, or review sites. The extra step required by a CAPTCHA can also play a role in reducing online harassment through inconvenience.
How Does CAPTCHA Work
CAPTCHAs work by providing information to a user for interpretation. Traditional CAPTCHAs provided distorted or overlapping letters and numbers that a user then has to submit via a form field. The distortion of the letters made it difficult for bots to interpret the text and prevented access until the characters were verified.
This CAPTCHA type relies on a human’s ability to generalize and recognize novel patterns based on variable past experience. In contrast, bots can often only follow set patterns or input randomized characters. This limitation makes it unlikely that bots will correctly guess the right combination.
Since CAPTCHA was introduced, bots that use machine learning have been developed. These bots are better able to identify traditional CAPTCHAs with algorithms trained in pattern recognition. Due to this development, newer CAPTCHA methods are based on more complex tests. For example, reCAPTCHA requires clicking in a specific area and waiting until a timer runs out.
Drawbacks of Using CAPTCHA
The overwhelming benefit of CAPTCHA is that it is highly effective against all but the most sophisticated bad bots. However, CAPTCHA mechanisms can negatively affect the user experience on your website:
Disruptive and frustrating for users
May be difficult to understand or use for some audiences
Some CAPTCHA types do not support all browsers
Some CAPTCHA types are not accessible to users who view a website using screen readers or assistive devices
CAPTCHA Types: Examples
Modern CAPTCHAs fall into three main categories—text-based, image-based, and audio.
Text-based CAPTCHAs
Text-based CAPTCHAs are the original way in which humans were verified. These CAPTCHAs can use known words or phrases, or random combinations of digits and letters. Some text-based CAPTCHAs also include variations in capitalization.
The CAPTCHA presents these characters in a way that is alienated and requires interpretation. Alienation can involve scaling, rotation, distorting characters. It can also involve overlapping characters with graphic elements such as color, background noise, lines, arcs, or dots. This alienation provides protection against bots with insufficient text recognition algorithms but can also be difficult for humans to interpret.
Text-based CAPTCHA patterns
Techniques for creating text-based CAPTCHAs include:
Gimpy—chooses an arbitrary number of words from an 850-word dictionary and provides those words in a distorted fashion.
EZ-Gimpy—is a variation of Gimpy that uses only one word.
Gimpy-r—selects random letters, then distorts and adds background noise to characters.
Simard’s HIP—selects random letters and numbers, then distorts characters with arcs and colors.
CAPTCHA Image
Image-based CAPTCHAs were developed to replace text-based ones. These CAPTCHAs use recognizable graphical elements, such as photos of animals, shapes, or scenes. Typically, image-based CAPTCHAs require users to select images matching a theme or to identify images that don’t fit.
You can see an example of this type of CAPTCHA below. Note that it defines the theme using an image instead of text.
Example of image-based CAPTCHA
Image-based CAPTCHAs are typically easier for humans to interpret than text-based. However, these tools present distinct accessibility issues for visually impaired users. For bots, image-based CAPTCHAs are more difficult than text to interpret because these tools require both image recognition and semantic classification.
Audio CAPTCHA
Audio CAPTCHAs were developed as an alternative that grants accessibility to visually impaired users. These CAPTCHAs are often used in combination with text or image-based CAPTCHAs. Audio CAPTCHAs present an audio recording of a series of letters or numbers which a user then enters.
These CAPTCHAs rely on bots not being able to distinguish relevant characters from background noise. Like text-based CAPTCHAs, these tools can be difficult for humans to interpret as well as for bots.
Math or Word Problems
Some CAPTCHA mechanisms ask users to solve a simple mathematical problem such as “3+4” or “18-3”. The assumption is that a bot will find it difficult to identify the question and devise a response. Another variant is a word problem, asking the user to type the missing word in a sentence, or complete a sequence of several related terms. These types of problems are accessible to vision impaired users, but at the same time they may be easier for bad bots to solve.
Social Media Sign In
A popular alternative to CAPTCHA is requiring users to sign in using a social profile such as Facebook, Google or LinkedIn. The user’s details will be automatically filled in using single sign on (SSO) functionality provided by the social media website.
This is still disruptive, but may actually be easier for the user to complete than other forms of CAPTCHA. An additional benefit is that it is a convenient registration mechanism.
No CAPTCHA ReCAPTCHA
This type of CAPTCHA, known for its use by Google, is much easier for users than most other types. It provides a checkbox saying “I am not a robot” which users need to select – and that’s all. It works by tracking user movements and identifying if the click and other user activity on the page resembles human activity or a bot. If the test fails, reCAPTCHA provides a traditional image selection CAPTCHA, but in most cases the checkbox test suffices to validate the user.
Imperva Bot Detection: CAPTCHA as a Last Line of Defense
Imperva provides a bot detection solution that is built for minimal business disruption. It offers several types of challenges which filter out bad bot traffic with minimal impact on human users—including device fingerprinting, cookie challenges and JavaScript challenges.
Imperva provides the option to deploy CAPTCHAs, but uses it as the final line of defense, if all other bot identification mechanisms fail. This means it will be used for a very small percentage of user traffic. Imperva does provide the option to manually enforce CAPTCHA, for websites that need a stricter approach to advanced bot protection.
In addition to providing bad bot mitigation, Imperva provides multi-layered protection to make sure websites and applications are available, easily accessible and safe. The Imperva application security solution includes:
DDoS Protection—maintain uptime in all situations. Prevent any type of DDoS attack, of any size, from preventing access to your website and network infrastructure.
CDN—enhance website performance and reduce bandwidth costs with a CDN designed for developers. Cache static resources at the edge while accelerating APIs and dynamic websites.
Cloud WAF—permit legitimate traffic and prevent bad traffic. Safeguard your applications at the edge with an enterprise‑class cloud WAF.
Gateway WAF—keep applications and APIs inside your network safe with Imperva Gateway WAF.
RASP—keep your applications safe from within against known and zero‑day attacks. Fast and accurate protection with no signature or learning mode.
The Pros And Cons Of CAPTCHAs | Should You Use Them?
The Pros And Cons Of CAPTCHAs | Should You Use Them? | Radware Bot Manager
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The Completely Automated Turing test to tell Computers and Humans Apart (CAPTCHA) was introduced to differentiate between genuine users and bots that have a negative impact on your online business. A CAPTCHA can protect your website by generating tests or puzzles that humans can pass, but bots can’t. Early CAPTCHAs displayed distorted letters, numbers, and words which can be read by humans but not by bots. Later versions show an assortment of images, from which users must select all the images that show a particular object such as a storefront or traffic signals. While they have proven to be useful in the battle against bots, it is essential to know when to use and when not to use them.
How and Where CAPTCHA is Used
To prevent comment spam
Malicious bots spam your website forms with unwanted messages and advertisements. They interfere in genuine user interactions and frustrate your users. If you have a website targeting a particular audience and you make use of comment forms, enabling CAPTCHA is one of the basic ways to prevent comment spamming to an extent. The downside is that it is presented to both genuine users and bots.
To stop fake registrations
Online businesses use forms for registration and signups and to provide services to their users. Bots usually target such forms and fill them with junk information, which skews the acquisition flow metrics for the business. CAPTCHA is usually implemented to stop such spam registrations from bots, but there are certain sophisticated bots that do bypass CAPTCHA and end up spamming forms.
Why You Should Avoid Using CAPTCHAs to Block Bots
Poor user experience
CAPTCHAs can be sometimes be time consuming and challenging, especially those with more complicated challenges such as text or image identification, which have earned notoriety for annoying users. Users may potentially switch to websites without CAPTCHAs due to frustration.
Not a foolproof remedy against bots
CAPTCHAs may protect your website from less sophisticated bad bots but resorting to CAPTCHAs to address the bot problem is not the best way. CAPTCHAs don’t distinguish between genuine users from bots, and indiscriminately require every visitor to solve them.
Alternatives to CAPTCHA
While it’s true that CAPTCHAs do block simple bots from spamming your website, advanced bots have started bypassing them by using outsourced teams that can even solve them in real-time. The most practical and least intrusive implementation would be to use an automated bot prevention solution that displays a CAPTCHA only when required to block bots. In-house bot detection tools require a lot of time and effort to run, but end up being ineffective due to constantly-evolving bot technologies and attack methods, making it a futile game of whack-a-mole.
More importantly to businesses, in-house solutions generally produce a high number of false positives (mistaking humans for bots) which leads to a poor user experience. Based on the nature and sophistication of bots, webmasters can choose to handle them in other ways including outright blocking, feeding them fake data, throttling or terminating their session, and dropping the connection entirely, among other options.
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Frequently Asked Questions about captca
What is CAPTCHA example?
CAPTCHAs are tools you can use to differentiate between real users and automated users, such as bots. CAPTCHAs provide challenges that are difficult for computers to perform but relatively easy for humans. For example, identifying stretched letters or numbers, or clicking in a specific area.
How do I enable CAPTCHA?
How to enable reCAPTCHA:Fill in the registration form, using information about your SilkStart website. … Copy the Captcha Site Key and Site Secret that reCAPTCHA gives you.Log in to your SilkStart site, and from the Admin Panel, go to Site > Website Settings, and paste in your Captcha Site Key and Site Secret.More items…•Apr 2, 2020
Is CAPTCHA good or bad?
CAPTCHAs may protect your website from less sophisticated bad bots but resorting to CAPTCHAs to address the bot problem is not the best way. CAPTCHAs don’t distinguish between genuine users from bots, and indiscriminately require every visitor to solve them.
