Printing Keys and using OCR.

Casey Jones groups at
Fri May 18 19:29:59 CEST 2007

James Cloos wrote:
> Use the OCRA font.  I did that in the past scaled so that the key used
> up most of a single letter sized sheet of paper.  I probably used mpage¹
> or enscript² to do the conversion to PostScript (it has been a while :).

> CTAN has metafont versions of OCRA and OCRB if you use TeX.
> You can get Type1 and TTF versions of OCRA from the ocr-a-font³ project
> on sourceforge.

> 3)

I got the the OCRA.ttf font from this link but it doesn't have the + - / 
and = characters used it the ascii ouptput of gpg. Do the fonts from 
CTAN have those chars. OCRA.ttf has a few other symbols. We could 
replace the + - / and = chars with the symbols in the OCRA.ttf font 
before printing. Perhaps also replace the lowercase L and the one and 
the zero and the uppercase O.

At first I was thinking that printing the keys in an ascii format would 
be superior to a barcode because it would be human readable(at least 
readable enough to retype), but then I realized that it wouldn't take 
much damage to the paper to render it unrecoverable. Barcodes are more 
resilient. But they're not human readable. Maybe the way to go is to use 
both. Or maybe we should create something like base64 but with error 
correction chars in both the horizontal and vertical direction. Or maybe 
we should just print multiple copies. Or maybe print in base16, though 
we'd still need/want error correction.

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