[texhax] Include Signatures on documents

[Reinhard Kotucha]

On 2013-07-16 at 11:52:22 -0400, William Adams wrote:

 > On Jul 16, 2013, at 9:46 AM, Alfredo Palhares wrote:
 > 
 > > Curious to see how you guys do it, has anyone ever
 > > automated/related the hand signature...
 > 
 > Time was I had a little side business making custom signature fonts
 > for use w/ mass mailings --- the issue of course w/ including a
 > good quality image of one's signature in a digital file is the ease
 > of copying --- I suppose the best thing to do would be to work up a
 > METAFONT which would do this,

Metafont creates bitmaps, it's certainly better to use MetaType1
instead.  The procedures are quite similar.  The advantage is that you
get a scalable vector font in Type 1 format which always looks better
than a bitmap font.

However, the expenditure of time can be enormous if one is not
familiar with these tools already.  What I would try first is to scan
the signature with the highest possible resolution, use a bitmap
manipulation program like GIMP in order to clean it up (remove noise),
and use potrace in order to turn it into vector graphics.

potrace can emit EPS and PDF directly.  If it's still necesseary to
manipulate the vector graphics, it's better to export it as SVG so
that it can be easily post-processed by Inkscape.  The latter can
export EPS and PDF as well.

 > then tweak its input slightly (using say the timestamp of the
 > document, or an MD5 hash of the doc's source) so that one could
 > verify when a given iteration of it should've been used --- a
 > modern twist to registrar ink.

Timestamps are not secure at all.  They can be changed at any time
(pdftk, qpdf).  SHA is more secure than MD5.  The only advantage of
MD5 is that MD5 hashes can be created by texlua/luatex, which makes
your TeX sources quite portable.

Regards,
  Reinhard

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Reinhard Kotucha                                      Phone: +49-511-3373112
Marschnerstr. 25
D-30167 Hannover                              mailto:reinhard.kotucha at web.de
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