Postage security device having cryptographic keys with a variable key length
AssigneePitney Bowes Inc.
InventorPerry A Pierce
Life of this patent
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Abstract
A cryptographic method for providing a level of security by a postage security device, which generates a digital token using a cryptographic key. When it is required to make a key change in order to improve the level of security, the postage security devices replaces the cryptographic key with a new cryptographic key, wherein the new cryptographic key has a key length that is equal to or greater than the replaced cryptographic key. The new cryptographic key can be generated by the postage security device based on a given key length, or selected from a plurality of replacement keys stored in a storage device.
Claims19
A postage security device, including a cryptographic key, for generating a digital token with a level of security, wherein the digital token is generated as proof of postage payment requested by a user who provides mailing parameters to the postage security device, and wherein the digital token is generated based on the provided mailing parameters in order to allow the user to produce an indicia on a mailpiece based on the digital token, said postage security device comprising:
- storage means for storing replacement keys;
- means for determining whether unused storage means for replacement keys is available and for reporting an error condition if unused storage means is not available;
- first means, responsive to a command for a key change, for providing a further cryptographic key to replace the cryptographic key;
- and
- second means, operatively connected to the first means, for generating a further digital token, based on the provided mailing parameters and the further cryptographic key, wherein the cryptographic key has a first key length and the further cryptographic key has a second key length, which is greater than the first key length, so as to improve the level of security associated with said postage security device.
A cryptographic method of providing a level of security by a twin postage security device, which generates a digital token using a cryptographic key, wherein the digital token is generated based on mailing parameters provided by a user who makes a request to the postage security device for proof of postage payment, and wherein the digital token allows the user to produce an indicia on a mailpiece as proof of postage payment, said method comprising the steps of:
- sending a signal to the postage security device requesting a key change;
- and
- requesting a second signal indicating whether unused key storage space for replacement keys is available;
- providing a new cryptographic key, in response to the signal if the second signal indicates that storage pace is available, in order to generate further digital tokens upon request, wherein the replaced cryptographic key has a first key length and the new cryptographic key has a second key length, which is greater than the first length, so as to improve the security of the postage security device.
A postage metering system to allow a user to produce an indicia on a mailpiece as proof of postage payment, said system comprising:
- a data center for receiving mailing parameters from the user and for providing data indicative of the mailing parameters;
- a postage security device, operatively connected to the data center, for receiving said data and for providing a token based on the mailing parameters and a cryptographic key and having storage means for storing replacement keys, and means for determining whether unused storage means for replacement keys is available and for reporting an error condition if unused storage means is not available;
- and
- means, operatively connected to the postage security device, for printing the indicia based on the token, wherein the postage security device is capable of replacing the cryptographic key with a new cryptographic key in response a signal requesting a key change, wherein the new cryptographic key has a second length, which is greater than the first key length, so as to improve the level of security of the postage metering system.
Dependencies are inferred from the claim text.