The maximum allowed size on a QR code is 3K, so trying to pass a 4K
private key as proposed will cause qrencode to fail:
$ gpg --export 5EA01078| ascii85 | qrencode -8 -o key.png
Failed to encode the input data: Input data too large
(ps.: I'm using --export, instead of --export-private-key, as I
don't have the private key used by the bug report)
Yet, we can use "head" command to truncate the size to something
that would work.
With that in mind, I did the following test with the upstream
version of ZBar[1]:
1. ASCII mode:
--------------
$ gpg --export 5EA01078| ascii85| head -10 > orig && cat orig | qrencode -8 -o
key.png && ./zbarimg/zbarimg --oneshot --raw key.png >parsed && diff -s orig
parsed
scanned 1 barcode symbols from 1 images in 0.05 seconds
Files orig and parsed are identical
2. Binary mode:
---------------
$ gpg --export 5EA01078 |head -c 2000 > orig && cat orig | qrencode -8 -o
key.png && ./zbarimg/zbarimg -Sbinary --raw --oneshot key.png >parsed && diff
-s orig parsed
scanned 1 barcode symbols from 1 images in 0.11 seconds
Files orig and parsed are identical
Summary:
--------
On both ASCII and binary mode, the output of the decoded image
is equal to the input data.
It should be noticed that, without "--oneshot", zbarimg will
output a "\n" after the parsed data, as the image may have
other codes on it.
So, this issue was already solved upstream.
[1] available at: https://github.com/mchehab/zbar
Thanks,
Mauro
