Re: Mikes request that we identify an upper limit on the number of digits

> For example a code with five digits is both too high  for accessibility 

One of the issues IBM opened against this SC is that to date you have 
supplied no data to support this statement, or to support the notion that 
transcription represents an impediment significant enough that an SC is 
warranted to entirely prevent its use to satisfy authentication. As 
mentioned in Issue #442 the only study cited so far was a study that 
showed that every participant was able to transfer 5 digits. So why keep 
repeating that 5 is too high?

I identified the concern to you last November and the concern about 
prohibiting copying was flagged and discussed back in April. Issue 442 has 
been open since October 8 with no response. This concern is not coming out 
of the blue, nor am I the only person to voice it.

Other considerations include identifying thresholds and relying on 
assistive technologies to augment experience to satisfy individual users 
needs. As an example, look at the thresholds for Contrast (Minimum). The 
SC demands a certain level of contrast for content. That is not going to 
satisfy the needs of all users, but based on a bunch of analysis and data, 
a threshold was established, with the assumption that a user who requires 
more contrast is going to call on an AT to augment.

My expectation would be that based on data, we would be looking at 
something similar for guidance on allowable transcription. If we don't 
have that data, then we are basing this SC on anecdotal evidence -- and as 
others have identified, it's an SC with far-reaching ramifications.

The new Animation from Interaction SC, designed to address vestibular 
disorders, had its timing parameters removed and its designation as a 
double AA moved to a triple A category because there was insufficient data 
to establish enforceable thresholds.

Michael Gower
IBM Accessibility
Research

1803 Douglas Street, Victoria, BC  V8T 5C3
gowerm@ca.ibm.com
voice: (250) 220-1146 * cel: (250) 661-0098 *  fax: (250) 220-8034



From:   "lisa.seeman" <lisa.seeman@zoho.com>
To:     "W3c-Wai-Gl-Request@W3. Org" <w3c-wai-gl@w3.org>
Date:   2017-11-28 12:45 AM
Subject:        Mikes request that we identify an upper limit on the 
number of  digits



Hi Folks

Mike had requested empirical evidence for what is the maximum number of 
digits that can be reliable copied form a device for multi factor 
authentication.

I am looking into it, but I actually think we should not enforce a  limit 
in the number of digits. Enforcing a limit on the number of digits in a 
security code will definitely jeopardize security. For example a code with 
five digits is both too high  for accessibility and lower then most secure 
applications would require.  It is much better to give the user an option 
of sending the code to the computer via Bluetooth/ token or even QR code. 

Please let me know if we want to go this rout. If not it is a lot of 
research for nothing. 

in the mean time Neil found some more research on sequencing problems that 
is useful in case we decide we would want to go in Mike's direction.

All the best

Lisa Seeman

LinkedIn, Twitter