Printing Keys and using OCR.
groups at caseyljones.net
Mon May 21 02:10:24 CEST 2007
> I just tried OCR-A but with limited success. Will add in par2 and see
> how things go with that.
That should be interesting.
I'm now leaning even more towards hex (base16) rather than base64. There
would be less opportunity for confusion for the OCR. I was thinking it
would be too inefficient but then I realized that hex gets four bits per
char and base64 only gets six, so hex is only 50% bigger. If the error
rate was sufficiently low, you might be able to get away with a much
smaller font as well. A font half the size would store four times as
much per page.
I'm thinking about writing a small simple script to print the hex with
parity or checksum or a simple error correction value at the side of
each row and the bottom of each column. The script that checks the
parity could mark the rows and columns with errors, thereby allowing you
to do human OCR to correct the errors if the characters hadn't been
obliterated and if there weren't too many errors.
As long as one is doing such a script one might as well pick 16 chars
that are more distinct than the usual 0-9A-F. A short sentence could be
put at the bottom of the page to tell how to decode it, or the script
itself might be included on another page.
More information about the Gnupg-users