Service provision authentication protocol
First Claim
1. A method, carried out by a customer unit that maintains a code sequence, for establishing a communications channel with a base station, comprising the steps of:
- receiving from the base station a digital signal sequence;
developing a string which includes the code sequence, the digital signal sequence, and a sequence of bits that is characteristic of the customer unit;
hashing the string to develop a hashed string; and
using the hashed string in further communications with the base station.
4 Assignments
0 Petitions
Accused Products
Abstract
A protocol for authenticating a cellular telephone to a service provider for the purpose of preventing the piracy of cellular services. A service provider assigns a unique "secret", along with other information such as a telephone number, to each cellular telephone when the telephone service is established with the service provider. Each base station of a service provider continuously broadcasts a periodically changing random number to all of the cellular telephones within the base station'"'"'s jurisdiction. When a cellular telephone first enters the jurisdiction of a base station, it registers itself with the base station by concatenating a secret password and the most recently broadcast random number, along with other information, and passing the concatenated information to a hash function. The cellular telephone then sends the output of the hash function, along with other identifying information to the service provider. The service provider, upon learning of the cellular telephone'"'"'s identity, feeds the secret assigned to that cellular telephone and the random number, along with other information, into the same hash function. When the result of the hashing performed by the service provider matches that provided by the cellular telephone, authentication for that cellular telephone is complete. Thereupon, the provider sends the cell a shared secret data field which is known to the mobile unit, and subsequent authentication processes are carried out between the mobile unit and the cell itself.
183 Citations
39 Claims
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1. A method, carried out by a customer unit that maintains a code sequence, for establishing a communications channel with a base station, comprising the steps of:
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receiving from the base station a digital signal sequence; developing a string which includes the code sequence, the digital signal sequence, and a sequence of bits that is characteristic of the customer unit; hashing the string to develop a hashed string; and using the hashed string in further communications with the base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, carried out by a customer unit that maintains a code sequence, for establishing a communications channel with a base station, comprising the steps of:
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receiving from the base station a digital signal sequence; developing a string which includes the digital signal sequence, a sequence of bits that is characteristic of said customer unit and a key derived from the code sequence; hashing the string to develop a hashed string; and sending the hashed string to the base station. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method, carried out by a customer unit that maintains a code sequence, for establishing a communications channel with a base station that has no knowledge of said code sequence, comprising the steps of:
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(a) receiving from said base station a digital signal sequence; (b) developing a string which includes (1) a substring containing a sequence of bits that is characteristic of said customer unit, (2) a substring that is related to a specified action to be taken by said customer unit, which substring is selected from a set comprising (i) a null string, (ii) a string of bits corresponding to a number assigned to said customer unit, and (iii) a string corresponding to the number of another customer unit to which connection is sought, (3) a substring containing said digital signal sequence, and (4) a substring containing a key derived from said code sequence; (c) hashing said string to develop a hashed string; and (d) sending said hashed string to said base station. - View Dependent Claims (22, 23, 24)
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25. A customer unit for communicating with a system, said customer unit including first means (200) for developing call initiation control signals and call progress control signals second means (210, 230, 240) responsive to said call initiation control signals and call progress control signals for establishing and maintaining a communication channel with said system in accordance with a protocol third means (200) for creating data signals, and fourth means (220) for applying the data signals and the call control signals to said communication channel, said second means CHARACTERIZED BY:
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a processor responsive to said third means and said fourth means; means A (a register in block
240) for developing an identifier signal that is unique to said customer unit;means B for storing (240) a temporary string signal (RAND) received from said system; means C for storing (232) an identifier signal (MIN) supplied by an owner of said system, a code sequence key signal (A-key) supplied by said owner of said system, an authentication key signal (SSD-A), and a speech encryption key signal (SSD-B); means D (231) responsive to said processor for hashing an applied string and developing thereby a hashed output; means E for applying said authentication key to means D. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A method carried out by a communications system for establishing a communications channel with a customer unit comprising the steps of:
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maintaining an authentication key of said customer unit; receiving a first hashed authentication string from said customer unit; forming a local authentication string by combining said authentication key with other information; hashing said local authentication string to form a local hashed authentication string; and comparing said local hashed authentication string with the first hashed authentication string. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification