@device(postscript)
@libraryfile(Mathematics10)
@libraryfile(Accents)
@style(fontfamily=timesroman,fontscale=11)
@pagefooting(immediate, left "@c<Technical Report 1996>",
center "@c<Computer Science>",
right "@c<Carnegie Mellon>")
@heading(Cryptographic Postage Indicia)
@heading(CMU-CS-96-113)
@center(@b(J. Doug Tygar, Bennet Yee, Nevin Heintze))
@center(January 1996)
@center(FTP: CMU-CS-96-113.ps)
@blankspace(1)
@begin(text)

We apply cryptographic techniques to the problem of fraud in metered
mail.  We describe a mail system that combines off-the-shelf barcode
technology, tamper-proof devices, and cryptography in a fully-integrated
secure franking system.  This system provides protection against:
@blankspace(.5)

@begin(enumerate)
Tampering with postage meters to fraudulently obtain extra postage;

Forging and copying of stamps;

Unauthorized use of postage meters; and

Stolen postage meters.
@end(enumerate)

We provide detailed justification for our design, and
discuss important tradeoffs involving scanning strategies,
encryption technology and 2-D barcode technology.
The US Postal Service' recent Information Based Indicia Program
(IBIP) announcement adopted the principal design features of
our model.

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@begin(transparent,size=10)
@b(Keywords:@ )@c<Cryptography, ranking, electronic currency, mail, postage,
stamps, electronic stamps, secure coprocessors, signatures>
@end(transparent)
@blankspace(1line)
@end(text)
@flushright(@b[(16 pages)])