True.  I probably should have called it "redundancy-tradeoff-space" or "sacrificial space".



On Friday, December 1, 2023 at 16:13, Thomas Dowling eloquently inscribed:

> 'Some QR codes have "favicon" graphics in dead-space of the QR code where
> they are ignored by the QR reader..'
> 
> I'm not sure it's fair to call it dead space. The cute little graphic in
> the middle of your QR code is taking advantage of - but also eating into -
> the redundancy and error correction built into the format. IOW, it
> deliberately damages the QR code knowing that it can get away with
> it, which it mostly can on web pages. Problems might arise once Charles'
> business card has gotten a little worn, or creased, or had some coffee
> spilled on it.
> 
> On Fri, Dec 1, 2023 at 3:38 PM Hammer, Erich F <[log in to unmask]> wrote:
> 
>> Charles,
>> 
>> Think of your QR code like a braille business card; A sighted recipient
>> would need to get it translated, but it's just your text information.  If a
>> blind, evil genius came along, what could they do with it?
>> 
>> Some QR codes have "favicon" graphics in dead-space of the QR code
>> where they are ignored by the QR reader, but you can't encode a logo
>> into the QR code any more than you could convert a logo into braille.
>> 
>> Erich
>> 
>> 
>> PS:  A related and little known -- by sighted people -- fact:  Braille is
>> heavily encoded and distinctly not "regular text" printed in a raised-dot
>> font.
>> 
>> 
>> On Friday, December 1, 2023 at 14:52, Charles Meyer eloquently inscribed:
>> 
>>> Tamarra and Deborah et al,
>>> 
>>> Thank you for your posts and questions.
>>> 
>>> Thanks to Erich I was able to create a QR code with zint although it
>>> doesn’t seem to allow me to add our County Library logo.
>>> 
>>> It does give me pause re: how that QR code could be used nefariously?
>>> 
>>> If I just invite a person to read my QR code with their cell phone QR
>>> reader could they misappropriate that QR code for unapproved activity?
>>> 
>>> Fascinating conversation.
>>> 
>>> I so appreciate all these helpful posts.
>>> 
>>> Charles.
>>> 
>>> Date:    Thu, 30 Nov 2023 09:12:50 -0800
>>> From:    Tamara Marnell <[log in to unmask]>
>>> Subject: Re: QR Code replacement for business card
>>> 
>>> A QR code just represents a string. If anything gets embedded, it will
>>> be visible in the text. Like in Joe's example, you'd see a different
>>> domain that forwards to the URL you wanted. If you test it and the
>>> decoded string is exactly what you put into the generator, it's fine.
>>> (Whether the website you visited to generate that code is safe is a
>>> different question, so I second the recommendation of Zint or the
>>> tools built into your browser.)
>>> 
>>> Most security risks of QR codes are really to the users. If the codes are
>>> posted in public places--like those little cards on restaurant tables to
>>> pay for your meal--someone could theoretically cover them up with a
>>> different code that tricks patrons into giving away their sensitive
>>> information, or downloads malware to their phones, etc.
>>> 
>>> -Tamara
>> 
>> 
>>