[15600] in cryptography@c2.net mail archive
Re: Security clampdown on the home PC banknote forgers
daemon@ATHENA.MIT.EDU (Richard Clayton)
Sun Jun 13 18:50:29 2004
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X-Original-To: cryptography@metzdowd.com
Date: Fri, 11 Jun 2004 18:06:14 +0100
To: cryptography@metzdowd.com
From: Richard Clayton <richard@highwayman.com>
In-Reply-To: <017630AA6DF2DF4EBC1DD4454F8EE297161658@rsana-ex-hq1.NA.RSA.NET>
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In article <017630AA6DF2DF4EBC1DD4454F8EE297161658@rsana-ex-
hq1.NA.RSA.NET>, Trei, Peter <ptrei@rsasecurity.com> writes
>>From the original article:
>
> "The software relies on features built into leading=20
> currencies. Latest banknotes contain a pattern of=20
> five tiny circles. On the =A320 note, they're disguised=20
> as a musical notation, on the euro they appear in a=20
> constellation of stars; on the new $20 note, the=20
> pattern is hidden in the zeros of a background=20
> pattern. Imaging software or devices detect the=20
> pattern and refuse to deal with the image."
>
>It would be interesting to figure out exactly what the
>'don't copy' information is. If it's really just five
>little circles, think of the fun you could have -
The circles act as a "do not copy" for recent models of colour
photocopier. They are NOT the mechanism involved in the latest round of
software detection by Adobe et al .. hence the fun is limited :(
The circles have been on UK and EU notes for some time, you can also see
them all over the latest US $20 bill. It is suggested that there is more
information to be extracted from the way that the basic five circle
units are combined together (said to identify the issuing bank), but no
firm results are known.
Just the five circles on an otherwise blank sheet are definitely
sufficient to cause the particular copier experimented with to indicate
the presence of currency. ie: it's all true :)
Markus Kuhn originally worked out the nature of the pattern in February
2002. It is now believed to have been invented by Omron, but this is
hearsay :( not something citable.
http://www.cl.cam.ac.uk/~mgk25/eurion.pdf
--=20
richard Richard Clayton
They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety. Benjamin Franklin
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