System and method of verifying cryptographic postage evidencing using a fixed key set
First Claim
1. A method for providing keys used in the verification of encoded information generated by a transaction evidencing device and printed on a document, the method comprising the steps of:
- generating a plurality of random verifier master keys to obtain a set of verifier master keys consisting of a fixed number of keys;
generating at least one pointer by applying a psuedorandom algorithm to data unique to the transaction evidencing device;
calculating a plurality of verifier token keys to obtain a verifier token key set corresponding to the set of verifier master keys; and
distributing the verifier token key set to verifiers.
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Abstract
A method for controlling keys used in the verification of encoded information generated by a transaction evidencing device and printed on a document comprises the steps of generating a plurality of random verifier master keys to obtain a set of verifier master keys consisting of a fixed number of keys; generating at least one pointer by applying a psuedorandom algorithm to data unique to the transaction evidencing device; calculating a plurality of verifier token keys to obtain a verifier token key set corresponding to the set of verifier master keys; encrypting the verifier token key set with a privacy key; and distributing the set verifier token keys and the privacy key to verifiers. The token keys are a function of the verifier master keys and a code valid for a limited time. The pointer algorithm is an appropriate symmetric key cryptographic algorithm and the code is function of a date dependent parameter. The master keys are distributed to postal and vendor data centers.
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Citations
11 Claims
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1. A method for providing keys used in the verification of encoded information generated by a transaction evidencing device and printed on a document, the method comprising the steps of:
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generating a plurality of random verifier master keys to obtain a set of verifier master keys consisting of a fixed number of keys; generating at least one pointer by applying a psuedorandom algorithm to data unique to the transaction evidencing device; calculating a plurality of verifier token keys to obtain a verifier token key set corresponding to the set of verifier master keys; and distributing the verifier token key set to verifiers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification