Cryptographic postage indicia

Abstract

Metered mail provides substantial opportunities for fraud. (Indeed, losses due to meter fraud in the United States are said to exceed $100 million annually.) We apply cryptographic techniques to prevent several types of improper use of metering indicia.This paper describes 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 postal indicia; 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 recently announced an Information Based Indicia Program (IBIP) [20, 21, 22, 23, 24] which adopts principal design features of our model. Beyond the intrinsic utility of this system, it also presents what is likely to be the first large scale use of public key infrastructure and microtrans-action technology.