How CAPTCHAs Affect Accessibility: Problems, Workarounds, and Alternatives

                     How CAPTCHAs Affect Accessibility: Problems, Workarounds, and Alternatives
               



Tópico:
                     How CAPTCHAs Affect Accessibility: Problems, Workarounds, and Alternatives
               
Categoria: Tutoriais | FreeCodeCamp Premium
Idioma Principal: Português (Conteúdo de Tecnologia)

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CAPTCHAs – or the "I am not a robot" challenges – were originally designed to separate humans from bots.

It started with deciphering some distorted text, then evolved into checking a box or boxes where an element is in an image. While CAPTCHAs can help websites determine whether the user is a human or a bot, they often present challenges to many real humans, especially those with disabilities.

Photo by Karen Grigorean on Unsplash

Table of Contents

• What is CAPTCHA?

• What Are the Issues with Visual CAPTCHAs?

• What Are the Issues with Auditory CAPTCHAs?

• What Are the Issues with Time-based CAPTCHAs?

• Common Workarounds and Accessible Alternatives

• Risk-Based Authentication

• Device-Based Trust

• Human-Friendly Verification

• Conclusion

What is CAPTCHA?

CAPTCHA is an acronym that stands for Completely Automated Public Turing test to tell Computers and Humans Apart. CAPTCHA was originally created to prevent automated systems from abusing websites. For example, an automated system creating thousands of fake accounts in a short amount of time.

CAPTCHA can be a visual recognition test, like selecting all images with traffic lights. CAPTCHA can be audio challenge, which can be a test to type from hearing an audio. CAPTCHA can also be time-based or interaction-based behavior tracking. Visual, audio and time-based CAPTCHAs all have their own unique set of usability and accessibility issues.

What Are the Issues with Visual CAPTCHAs?

Image-based CAPTCHAs are one of the most common formats today. Visual CAPTCHA's are the tests where we you'd see nine square boxes and have to select all of the boxes with traffic lights. They are also tested with one large image broken down into nine squares, and the user has to select the boxes where traffic lights appear. The visual CAPTCHAs create barriers for many people, such as people with visual impairments like blindness, low vision, color blindness.

First, the visual tests are often poorly compatible with screen readers as they are often not properly labeled for assistive technologies like screen readers, which creates an issue for users who rely on them.

In addition to issues with screen readers, how many times have you tried to complete a CAPTCHA where a sliver of a traffic light was in another square and you didn't know if the test wanted you to select that box as well? I personally had issues verifying if the CAPTCHA test wanted me to select a square with a sliver of an image. Some CAPTCHAs have extremely low color contrast where I had issues figuring out the distorted text.

Some of the tests and images are ambiguous and create confusion for users. Audio CAPTCHA is an alternative approach to those that struggle with visual CAPTCHAs. Audio also comes with it's own set of usability and accessibility issues.

What Are the Issues with Auditory CAPTCHAs?

The visual CAPTCHA tests often come with an auditory equivalent for users who want to complete the test with auditory clues. The tests often have a button for the user to click and hear the visual clues. The user needs to enter the correct clue they hear in order to complete the CAPTCHA.

While the auditory CAPTCHA provides an alternative way for a user to complete the assignment, these often come with their own challenges. For example, they are frequently hard to understand due to distortion. Also, what if the user tries to complete t

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