CAPTCHA Lacks Accessible Way to Complete

Short Description

Captcha challenge may be fully dependent on sight, or aspects of completing the challenge are not accessible by using only the keyboard

Long Description

  • CAPTCHA's are inconvenient to most people, but visual emphasis can make them entirely unusable to blind and low vision users.
    • The same characteristics that make the letters and numbers harder for invasive technology—technology that the Captcha is trying to evade-- to read can make it difficult or impossible for a low vision user to decipher the proper letters and numbers.
  • Since the letters and numbers in a CAPTCHA are images, not text, a screen reader cannot read them at all.
  • When an audible alternative is available, a CAPTCHA is more accessible to low vision and blind users; however, the audible option has background noise and the letters and numbers are distorted, sometimes to the extent that it is impossible to understand. Furthermore, it is often necessary to be in a quiet place and to listen multiple times to decipher all the characters.
  • Some of the more recent versions of CAPTCHA are more accessible, in that they observe the user's behavior, but the fall back options are usually a standard CAPTCHA with the aforementioned problems.

Example of Issue

Recommendations

  • Because traditional CAPTCHA where a user has to decipher either a visual or audible code is anywhere from annoying to completely unusable for most people, consider alternatives that also help to deter bots. Some examples include automated and manual spam detection services, honeypot (with message not to fill out the field because screen readers will find it), time stamps, temporary tokens, and multi factor authentication (assuming users will have access to a phone).
  • There are a number of more accessible forms of CAPTCHA as well. Some examples include No CAPTCHA and text CAPTCHA logic questions.
  • At the very least, make sure a CAPTCHA provides both visual and audible options.
  • Make sure that the fallback CAPTCHA provided for any of the alternatives is at least minimally accessible by being keyboard accessible and both audible and visible.

Accessibility/Usability

Accessibility
Usability

Impacted Assistive Technology

Screen Reader
Screen Magnifier

Impacted Type of Device

Computer
Mobile