Security system comprising three apparatuses sharing a time-varying code
First Claim
1. In an electronic security system comprising an access-granting apparatus, a linking apparatus and a central computer issuing a link code segment, the access-granting apparatus comprising an access clock having an output, and an access computer having an access memory, the linking apparatus comprising a link memory, the linking apparatus receiving the link code segment from the central computer and communicating the link code segment to the access-granting apparatus which thereupon grants access to a protected apparatus if the link code segment matches an access code segment stored in the access memory, the access-granting apparatus otherwise thereupon denying access thereto, an improvement whereinthe central computer comprises a master clock having an output communicated by a first synchronization means to the access clock whereby the access clock is synchronized to the master clock, andthe linking apparatus comprises a linking clock and a linking computer operatively associated with the linking memory, the output of the master clock communicated by a second synchronization means to the linking apparatus whereby the linking clock is synchronized to the master clock.
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Accused Products
Abstract
Complex, time varying codes (e.g., pseudo-random sequences) are used in an access regulating system that includes three types of synchronized apparatuses. The first apparatus is a central computer, or other suitable means that issues a set of time-dependent code segments to a plurality of the second, linking, type of apparatus (which may comprise end-user communication equipment). The codes are relayed by the linking apparatus to the third, access granting, apparatus that grants access (e.g., to a communication network) only if there is a match between the code from the linking apparatus and a code stored in the access granting apparatus.. The time-varying code segments are chosen so that after the expiation of a predetermined interval none of the code segments in the linking apparatus match code segments in the access-granting apparatus.
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Citations
5 Claims
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1. In an electronic security system comprising an access-granting apparatus, a linking apparatus and a central computer issuing a link code segment, the access-granting apparatus comprising an access clock having an output, and an access computer having an access memory, the linking apparatus comprising a link memory, the linking apparatus receiving the link code segment from the central computer and communicating the link code segment to the access-granting apparatus which thereupon grants access to a protected apparatus if the link code segment matches an access code segment stored in the access memory, the access-granting apparatus otherwise thereupon denying access thereto, an improvement wherein
the central computer comprises a master clock having an output communicated by a first synchronization means to the access clock whereby the access clock is synchronized to the master clock, and the linking apparatus comprises a linking clock and a linking computer operatively associated with the linking memory, the output of the master clock communicated by a second synchronization means to the linking apparatus whereby the linking clock is synchronized to the master clock.
Specification