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CAPTCHA Comment: character based section I18N considerations [I18N] (#29)

From: Janina Sajka <janina@rednote.net>
Date: Mon, 3 Jun 2019 19:04:12 -0400
To: public-rqtf@w3.org
Message-ID: <20190603230412.GA32586@rednote.net>
Scott:

Would you be able to take on incorporating this comment into our draft?

This comment is from the I18N review we requested early in May and comes
via github here:

https://github.com/w3c/apa/issues/29

If not, no worries. Just advise. Thanks!

Janina

Addison Phillips writes:
> 2.1.1 Traditional Character-Based CAPTCHA
> https://w3c.github.io/apa/captcha/#traditional-character-based-captcha
> 
> > While some sites have begun providing CAPTCHAs utilizing languages other than English, an assumption that all web users can understand and reproduce English predominates. Clearly, this is not the case. Arabic or Thai speakers, for example, should not be assumed to possess a proficiency with the ISO 8859-1 character set [iso-8859-1], let alone have a keyboard that can easily produce those characters in the CAPTCHA's form field. Research has demonstrated how CAPTCHAs based on written English impose a significant barrier to many on the web; see Effects of Text Rotation, String Length, and Letter Format on Text-based CAPTCHA Robustness [captcha-robustness].
> 
> The above text has several potential issues:
> 
> 1. ISO8859-1 ("Latin-1") is possibly not the best reference here, since probably is what is meant are ASCII letters and digits. The difference between Latin-1 and ASCII are the various accented letters, which are not widely used in CAPTCHA.
> 2. Virtually all computing systems have a means of inputting ASCII, so saying that users might not have a "keyboard that can easily produce those characters" is probably false. 
> 3. The reverse is not true. Producing CAPTCHA images containing non-ASCII text may prove difficult to use if the user does not have the appropriate keyboard available. It is difficult to determine on the server side what the input capabilities of a given user agent includes.
> 4. Many characters or writing systems are difficult to discern when distorted. This includes accented Latin-script letters, cursive scripts such as Arabic, and of course Han ideographs.
> 5. It has been observed that using actually words for CAPTCHA improves accuracy, but or course this depends on being fluent in the language in question.
> 
> *This comment is part of the I18N horizontal review. *
> 
> -- 
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> Reply to this email directly or view it on GitHub:
> https://github.com/w3c/apa/issues/29

-- 

Janina Sajka

Linux Foundation Fellow
Executive Chair, Accessibility Workgroup:	http://a11y.org

The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
Chair, Accessible Platform Architectures	http://www.w3.org/wai/apa
Received on Monday, 3 June 2019 23:04:38 UTC

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