Prepaid smart card in a GSM based wireless telephone network and method for operating prepaid cards
First Claim
1. A method for enabling service from a wireless telephone having a Subscriber Identification Module (SIM) and a prepaid card in the telephone comprising the steps of:
- (a) calculating in the card a certificate as a function of(i) number of prepaid units remaining in the card,(ii) serial number in the card, and(iii) a key number in the card;
(b) transferring from the card to the SIM(i) said number of prepaid units remaining in the card, and(ii) the card'"'"'s serial number;
(c) calculating in the SIM a number which should be the same as the card key number based on said transferred number of prepaid units remaining in the card and said card serial number;
(d) calculating in the SIM a certificate as a function of said transferred number of prepaid units remaining in the card and said calculated number which should be the same as said key number in the card;
(e) comparing said calculated certificates from said card and from said SIM; and
(f) if coincident in said comparison then enabling said telephone in a wireless network.
1 Assignment
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Accused Products
Abstract
The invention provides a prepaid smart card to be used in a wireless telephone network, and methods for prepaying for wireless telephone services, as well as systems for operating a wireless telephone network with prepaid smart cards. The cards, methods and systems permit the use of wireless telephones anonymously, and/or the payment by a user without having a subscription. The invention requires minimal changes to the existing wireless telephone and wireless telephone network, yet provides security against abuse or fraudulent use of the telephone system. Additionally, promotional material may be provided with the prepayments, and persons may prepay into a subscriber'"'"'s telephone.
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Citations
26 Claims
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1. A method for enabling service from a wireless telephone having a Subscriber Identification Module (SIM) and a prepaid card in the telephone comprising the steps of:
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(a) calculating in the card a certificate as a function of (i) number of prepaid units remaining in the card, (ii) serial number in the card, and (iii) a key number in the card; (b) transferring from the card to the SIM (i) said number of prepaid units remaining in the card, and (ii) the card'"'"'s serial number; (c) calculating in the SIM a number which should be the same as the card key number based on said transferred number of prepaid units remaining in the card and said card serial number; (d) calculating in the SIM a certificate as a function of said transferred number of prepaid units remaining in the card and said calculated number which should be the same as said key number in the card; (e) comparing said calculated certificates from said card and from said SIM; and (f) if coincident in said comparison then enabling said telephone in a wireless network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for enabling service from a wireless telephone having a Subscriber Indentification Module (SIM) and a prepaid card in said telephone comprising:
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(a) means for calculating in the card a certificate as a function of (i) number of prepaid units remaining in the card, (ii) serial number in the card, and (iii) a key number in the card; (b) means for transferring from the card to the SIM (i) said number of prepaid units remaining in the card, and (ii) the card'"'"'s serial number; (c) means for calculating in the SIM a number which should be the same as the card key number based on said transferred number of prepaid units remaining in the card and said card serial number; and (d) for calculating in the SIM a certificate as a function of said transferred number of prepaid units remaining in the card and said calculated number which should be the same as said key number in the card (e) means for comparing said calculated certificates from said card and from said SIM, and if coincident in said comparison then enabling said telephone in a wireless network. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 25, 26)
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22. A subscriber identification module for operating with prepaid cards and with a wireless telephone network that provides goods/services via said wireless telephone network comprising:
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an integrated circuit having, (a) an input for receiving from one prepaid card (i) a serial number of said card, (ii) a number of prepaid units remaining in said card, and (iii) a certificate compiled by said card from its serial number, card key number, algorithm, and number of prepaid units remaining in said card; (b) a diversification key which is the same for a plurality of subscriber identification modules of said wireless telephone network; (c) first and second algorithms; (d) a microprocessor for calculating (i) a card key number with said first algorithm as a function of said diversification key, and said receive serial number of said card, and where said calculated card key number should be the same as said key number in said card; and (ii) calculating a certificate with said second algorithm as a function of said calculated card key number, and said receive number of prepaid units remaining in said card; and (iii) comparing said calculated certificate with said received certificate, and (iv) if coincidence, generating an enable signal whereby goods/services are provided in accordance with said generated enable signal. - View Dependent Claims (23, 24)
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Specification