Captchas
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.
Why reCAPTCHA is actually an act of human torture – TheNextWeb
Like many things that start out as a mere annoyance, though eventually grow into somewhat of an affliction. One particular dark and insidious thing has more than reared its ugly head in recent years, and now far more accurately described as an epidemic disease. I’m talking about the filth that is reCAPTCHA. Yes that seemingly harmless question of “Are you a human? ” Truly I wish all this called for were sarcastic puns of ‘The Matrix’ variety but the matter is far more describes reCAPTCHA as:[reCAPTCHA] is a free security service that protects your websites from spam and ever, this couldn’t be further from the truth, as reCAPTCHA is actually something that causes abuse. In fact, I would go so far as to say that being subjected to constant reCAPTCHAs is actually an act of human torture and disregard for a person’s human right of mental in the 90s a bunch of smart-asses realized money was to be made and much time saved by programming bots to do everything for them online. Some bots were good and helpful and made things easier and more efficient for everyone. Whilst others were used to send spam and even caused some websites to crash or suffer lag due to repeated a time websites employed easily defeated methods for trying to prevent such abuse by making anyone (or anything) who visited/accessed page ‘x’ do ‘y’ thing. Mostly these preventative methods were something stupidly easy for even a computer/bot to solve and did little to stop spam and misuse except prevent access from those only computers/bots that didn’t have a method of solving such simple solve what was (at the time) an epidemic in and of itself of bots, reCRAPCHA was edit: *Although the topic of ‘who made reCAPTCHA? ’ is mostly irrelevant as far as this post’s topic is concerned. I was firmly, albeit still mostly ‘kindly’ reminded that Mr. Luis von Ahn is the inventor of reCAPTCHA and who sold it to Google after ~2 years. * In my defense, the above wording is still right but as an author you have my apologies for not dropping your name sooner Mr. came to the rescue of all, as was arguably their responsibility because they were the ones taking it up the rear the hardest from such bots. With the torch now passed to Google, and in really no better shape than the original countermeasure. The below example is what you were tasked with solving, which in hindsight seems fair enough, though in reality – it’s incredulous to early something like this frustrated people and it wasn’t outsmarting computers either so it was time for Google to get “smart” and being Google, of course they realized they could kill two birds with one stone. So they came up with a way that almost no one was able to criticize them. They turned to making people solve reCAPTCHAs that were actually helping transcribe written works into digital format, searchable by OCR (Optical Character Recognition) am I talking about? Well do you remember the days when a reCAPTCHA suddenly went from looking like gobbledegook, to looking like this:I know I do. I solved thousands of these myself. A simple quick single or double word combination which could also be played out via audio. Mildly annoying but quick and simple for humans, and apparently hard for computers. Except when it became trivial for computers. So Google had to up the started out as the lesser of two evils, the good guy vs the bad guys. Except now the fight has evolved into a level of complete disregard for humanity thanks to the likes of these barstads. Yep that’s exactly what it looks like. A “Professional” company that literally EMPLOYS PEOPLE TO SOLVE OTHER PEOPLE’S wait it can’t be that ba-coughcoughcoughcOuGhand the list goes on, and on, and on…How to meet the resistance in battle? Well, fast-forward to now and you’ve got this disease that is reCAPTCHA v2. The piece of crap that you now find front-and-fucking-center of every single login/register page or text/form submission on the web. That beast that ‘blocks your path’ every time you want or need to login or write anything 2017 and 2018, the average time to solve one of these annoyances was a mere 8 seconds for most people. I personally could do them in about 2-3 if I’d had my coffee. In fact, people are doing studies on how long it takes different types of people to solve them. Such as this one here. Though mind you, it’s from back in 2015 where you could solve these in seconds with both hands tied behind your now? Now? THE AVERAGE TIME IS OVER 30 SECONDS! But don’t for one second think it has anything to do with some increasing level of complexity in the war against bots. No, no, no. How long it takes to now solve these things has increased due to completely deliberate and specific choices that Google has made in reCAPTCHA v3! Yes, I do mean v3 here because these changes (increased complexity in v2) were only made after the arrival of v3. I’m talking about why, despite you being a completely normal human being of sound deductive capability. You… just… keep… FAILING these things! So why… why does this happen? It isn’t because you are in fact a dunce who cannot count up to three or cannot tell how many buses or traffic lights there are in a few blurry photos and it also isn’t because you don’t know what a fire hydrant looks like. The reason that people fail reCAPTCHA v3 prompts so consistently now is because Google realized there was no punishment to forcing people to solve more of these ‘human verification puzzles’ and only more to gain by forcing (yes it IS forcing) people to train their AI for free. “People whine non-stop about hidden crypto-miners in websites but those are in fact a far more honest take of the kind of beast reCAPTCHA is. ”In short. GREED is the reason why you are doomed to fail at least 2 to 3 times every time one of these blocks your path. In fairer times it used to be that if you had recently finished one, Google could tell and you would be able to outright skip any additional annoying puzzle or prompt after you had recently finished one used to be that Google recorded a bit of your mouse movements and any other inputs you made and if those were ‘human enough’ you were spared the expense and agony of having to dance like a monkey to a tune. But no more. There are no short-cuts now. No free passes. It doesn’t matter if you’re logged into your Google account and allowing all manner of, despite its ability to track you even through every single reCAPTCHA prompt. They STILL force you to solve these things even though they know damn well you’re not a robot. Why? Because fuck you, that’s why! “We have now hit such a dystopian phase in internet history that some people are in the business of hiring humans to sit in front of a screen and just solve other people’s reCAPTCHA prompts. ”Things are only set to get worse too, and [I’m certainly to the only one who thinks so. When we hit reCAPTCHA v4 and beyond the time that it takes to solve these prompts will arguably get longer and the tasks become more will likely be asked to turn on your webcam to confirm you are a human, and not in fact a pesky cat that just stepped onto the will likely be asked to enable access to your microphone and forced to sing the chorus to the likes of Billy Ray Cyrus’ – Achy Breaky will likely be asked to open your phone/iPad/whatever and perform some action on a device other than the one you are trying to solve the reCAPTCHA on –all begging the question of “I mean do you really I mean really need to login or submit that post? What if you try later… Maybe it will just go away? If …YOU WILL WANT TO PAY A COMPANY TO SOLVE THESE THINGS FOR YOU. BUT YOU WON’T BE ABLE TO AFFORD IT! Solving reCAPTCHAs will be just another LUXURY like fast download and upload speeds, 4K displays and toilet paper that doesn’t give you a hold up, if you don’t think that before you start to even consider that there must be a way to bypass or block these things just like you can block an advertisement online. Leading you to find one of those aforementioned ‘solving services’ and actually ever sign up to one of there will, and, not LONG, before you ever could get to that stage, be an option to PAY GOOGLE THEMSELVES some form of subscription to bypass these things altogether. If such a thing sounds like a fairytale to you, my dear reader, you are very naïve. I call it the reCAPTCHA Pass I dare say it’s already in the works and that, if you value your time, you will want one. With Google controlling the supply, demand and complexity of these bloody things, you can bet that their prices will be the cheapest! Really I’m surprised there isn’t a freaking crypto ‘credit’ service that exists that you can use to pay your way out of having to do them. Now wait, that’s an idea! BRB whilst I go patent My. Words. It will only get worse and there will be multiple businesses and services available pining for your money. ‘When computers attack’ the only thing that can solve the question of “Are you a human? ” is literally exactly that, a human. Either you, or some poor sod you are paying. So what’s it gonna be? This article was originally published by Nils Gronkjaer. You can read it here.
Published August 23, 2019 – 2:53 pm UTCBack to top
Frequently Asked Questions about captchas
What are CAPTCHAs used for?
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.
Why am I getting so many CAPTCHAs?
CAPTCHAs can be caused by a variety of reasons including when a browser that may be a bot is detected, when a user attempts to login from an IP address with a poor reputation (VPNs, Tor, bot-nets, etc.), or after rapid-succession login attempts.
Why is reCAPTCHA so bad?
The reason that people fail reCAPTCHA v3 prompts so consistently now is because Google realized there was no punishment to forcing people to solve more of these ‘human verification puzzles’ and only more to gain by forcing (yes it IS forcing) people to train their AI for free.Aug 23, 2019
