Cryptographic Postage Indicia,

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 1 Tampering with postage meters to fraudulently obtain extra postage 2 Forging and copying of stamps 3 Unauthorized use of postage meters and 4 Stolen postage meters. 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 15 announcement adopted the principal design features of our model.