Two-way paging system having reverse channel message frequency authentication
First Claim
1. A two-way paging system comprising:
- (a) at least one two-way pager operative to formulate a reverse channel message for transmission on a reverse channel frequency, said reverse channel message including at least a message portion and a checksum portion, said chechsum portion dependent upon said message portion and said reverse channel frequency in a predetermined manner;
(b) a plurality of paging receivers for receiving said reverse channel message transmitted by said pager, said paging receivers calculating an authentication checksum based upon said message portion and said reverse channel frequency in said predetermined manner, said paging receivers rejecting said reverse channel message unless said authentication checksum matches said checksum portion in said reverse channel message.
1 Assignment
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Accused Products
Abstract
A method of modifying reverse channel messages in a two-way paging system (101) to authenticate reverse channel messages is disclosed. The intended frequency of the reverse channel message is converted into a unique binary integer. The binary integer is used to modify a checksum (207) in the reverse channel message so that the checksum is now dependent upon not only the message (205) contents but also the intended frequency of the reverse channel message. When received by a paging receiver (109) of the paging system, an identical calculation takes place and if the modified checksum transmitted with the reverse channel corresponds with the calculated checksum, the message is authenticated. Otherwise, the reverse channel message is rejected.
24 Citations
6 Claims
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1. A two-way paging system comprising:
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(a) at least one two-way pager operative to formulate a reverse channel message for transmission on a reverse channel frequency, said reverse channel message including at least a message portion and a checksum portion, said chechsum portion dependent upon said message portion and said reverse channel frequency in a predetermined manner; (b) a plurality of paging receivers for receiving said reverse channel message transmitted by said pager, said paging receivers calculating an authentication checksum based upon said message portion and said reverse channel frequency in said predetermined manner, said paging receivers rejecting said reverse channel message unless said authentication checksum matches said checksum portion in said reverse channel message. - View Dependent Claims (2)
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3. A two-way pager including:
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(a) a receiver for receiving messages transmitted by a two-way paging system; (b) a transmitter for transmitting reverse channel messages to said two-way paging system on a reverse channel frequency; (c) a microprocessor connected to said receiver and said transmitter, said microprocessor operative to formulate said reverse channel message for transmission on said reverse channel frequency, said reverse channel message including at least a message portion and a checksum portion, said checksum portion dependent upon said message portion and said reverse channel frequency in a predetermined manner. - View Dependent Claims (4, 6)
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5. A method for authenticating a reverse channel message transmitted by a two-way pager on a reverse channel frequency in a two-way paging system, said method comprising the steps of:
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(a) formulating said reverse channel message for transmission by said two-way pager, said reverse channel message including at least a message portion and a checksum portion, said checksum portion dependent upon said message portion and said reverse channel frequency in a predetermined manner; (b) receiving said reverse channel message by said two-way paging system, said two-way paging system calculating an authentication checksum based upon said message portion and said reverse channel frequency in said predetermined manner, said two-way paging system rejecting said reverse channel message unless said authentication checksum matches said checksum portion in said reverse channel message.
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Specification