Printing Keys and using OCR.

Joseph Oreste Bruni jbruni at
Tue May 15 17:45:09 CEST 2007

How about bar code? I don't know long it would be to hold a key though.
That might exceed the capabilities of some bar-code scanners.

PGP Fingerprint:
C54A C9DD 84AD C6FC D343  67C4 5195 D63A CD55 18C7

On Tuesday, May 15, 2007, at 12:23AM, "Roscoe" <eocsor at> wrote:
>Hey folks,
>I'm wanting to store my OpenPGP key on paper, I suspect this is
>something someone else has already done. The motivation behind this is
>that paper is the most stable backup medium I have.
>I have tried printing out a key, then scanning and using gocr on the result.
>That was unsuccessful due to the high number of errors in the OCR
>phase, I suspect with a carefully selected font and font size I could
>sigificantly cut down on that error rate.
>Now since even a 99.99% accuracy in the OCR phase is still going to
>cause a large headache when you're trying to track down what one or
>few characters got interpreted wrong amongst a screenfull of them, I
>thought some error correction would be a very good idea.
>(First thing that came to mind was par2+base64 but I think this might
>have have a few issues.).
>Then came the realisation that printing out english letters was a
>woefully inefficent way to store binary data on a piece of paper. I'm
>certain there must be more compact and robust ways (ie: without subtly
>similar symbols like 0 and O) way to store information.
>So...Does anyone :
>Know of a system that can take binary data and output an image to be
>printed out, that is then capable of extracting that binary data from
>an imperfect scan of the image.
>OR Have any success stories regarding printing, scanning then OCRing
>keys or any other data?
>If so how did you do it? (what did you use for error correction, what
>font, what size etc..)
>(Oh, and I'm aiming to do this with just Free/Open software.)
>-- Roscoe
>Gnupg-users mailing list
>Gnupg-users at

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