Security in cellular telephones
First Claim
Patent Images
1. A method of assigning a security code to a cellular telephone, which stores a number X, an index I, and a serial number ESN, comprising the following steps:
- a) maintaining a table (12) with a custodian (TIA), which table contains multiple pairs of numbers, each pair associating an index I with a number X;
b) receiving an index I from the cellular telephone;
c) transmitting the index I to the custodian (TIA);
d) causing the custodian (TIA) toi) identify the number X associated with the transmitted index I in the table,ii) generate a random number RAND, andiii) generate a mask E, based on X and RAND,e) selecting a security code A13 Key;
f) masking the security code A13 Key with the mask E, to produce a number Z; and
g) transmitting number Z and the random number RAND to the cellular telephone.
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Accused Products
Abstract
A system for delivering a security code to a cellular telephone. The cellular telephone holds a key X. The cellular telephone requests that an Authorization Center, AC, assign a security code to the cellular telephone. The AC selects a security code, and encrypts it, such that key X is effective to de-crypt the code, yet the AC does not know key X.
12 Citations
7 Claims
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1. A method of assigning a security code to a cellular telephone, which stores a number X, an index I, and a serial number ESN, comprising the following steps:
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a) maintaining a table (12) with a custodian (TIA), which table contains multiple pairs of numbers, each pair associating an index I with a number X; b) receiving an index I from the cellular telephone; c) transmitting the index I to the custodian (TIA); d) causing the custodian (TIA) to i) identify the number X associated with the transmitted index I in the table, ii) generate a random number RAND, and iii) generate a mask E, based on X and RAND, e) selecting a security code A13 Key; f) masking the security code A13 Key with the mask E, to produce a number Z; and g) transmitting number Z and the random number RAND to the cellular telephone. - View Dependent Claims (2, 3)
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4. A method of assigning an A-key to a wireless telephone, which functions as a serial number of the wireless telephone in billing matters, comprising the following steps:
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a) maintaining an algorithm in the wireless telephone which i) produces the A-key when given a first code (RAND), a second code (Z), and a third code (X2), and ii) requires the first, second, and third codes collectively to produce the A-key; b) maintaining the third code (X2) within the wireless telephone; c) receiving, from a remote party, the first and second codes (RAND, Z) at the wireless telephone and delivering them to the algorithm; d) delivering the third code (X2) to the algorithm; and e) producing the A-key from the algorithm, using RAND, Z, and X2, and storing the A-key within the telephone. - View Dependent Claims (5)
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6. A method of assigning an A-key to a wireless telephone, which functions as a serial number of the wireless telephone in billing matters, comprising the following steps:
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a) maintaining an algorithm in the wireless telephone which i) produces the A-key when given a first code (RAND), a second code (Z), and a third code (X2), and ii) requires the first, second, and third codes collectively to produce the A-key; b) transmitting two codes, I and ESN, from the wireless telephone to a telephone service provider; c) relaying the code I from the telephone service provider to a third party (TIA); d) causing the third party (TIA) to i) ascertain the value of the third code (X2) from a table, based on code I; ii) generate a random number (RAND); iii) apply the ascertained value of the third code (X2) and the random number (RAND) to a non-reversible algorithm, to produce a mask (E); and iv) transmit the mask (E) to the telephone service provider; e) causing the telephone service provider to i) select an A-Key; ii) mask the A-Key, using the mask (E), to produce a transmission code (Z); and iii) transmit the transmission code (Z) and the random number (RAND) to the wireless telephone; and f) causing the wireless telephone to i) produce the mask (E), based on the received random number (RAND), and the non-received third code (X2); ii) produce the A-key, based on the received transmission code (Z) and the mask (E); and iii) store the A-key.
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7. A system for assigning an A-key to a wireless telephone, comprising:
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a) a first party (TIA); b) a second party (AC); c) means, which utilizes processing undertaken by the first and second parties, which i) selects the A-key ii) enables the second party (AC) to deliver the A-key, in encrypted form, to the wireless telephone, without access to a key effective to extract the A-key from its encrypted form, and iii) transmits no data to the wireless telephone from which the A-key can be derived by another party.
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Specification