Electronic kay storing time-varying code segments generated by a central computer and operating with synchronized off-line locks
First Claim
1. In an electronic security system comprising an access-regulating apparatus, a linking apparatus and a centrals means of issuing a link code, said access-regulating apparatus comprising an access clock having an output, an access computer having an access memory, and an actuator, said linking apparatus comprising a link memory, said linking apparatus receiving said link code from said code issuing means and communicating said link code to said access regulating apparatus, whereby said actuator acts under control of said access computer if said link code matches an access code stored in said access memory, an improvement wherein said access computer uses an access code generating algorithm having as inputs said output of said access clock, an epochal time datum and an initial state datum to generate said access code.
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Abstract
Complex, time varying codes (e.g., pseudo-random sequences) are used in an access regulating system that includes a number of synchronized elements. The system includes a central computer, or other suitable means to issue one or more time-dependent linking codes that are stored in a memory in a linking device (e.g., a hotel door key) from whence the codes are relayed to an access regulating device (e.g., a hotel door lock) that permits a user access if a stored link code matches a current access code. In a preferred system a trusted central computer and all the access regulating apparatuses have a common epochal time and a common time interval during which a given code is valid. Each access regulating apparatus uses a unique combination of start and tap vectors, known only to the specific access regulating device and to the central computer, to generate a pseudo-random access code for each time interval.
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20 Claims
- 1. In an electronic security system comprising an access-regulating apparatus, a linking apparatus and a centrals means of issuing a link code, said access-regulating apparatus comprising an access clock having an output, an access computer having an access memory, and an actuator, said linking apparatus comprising a link memory, said linking apparatus receiving said link code from said code issuing means and communicating said link code to said access regulating apparatus, whereby said actuator acts under control of said access computer if said link code matches an access code stored in said access memory, an improvement wherein said access computer uses an access code generating algorithm having as inputs said output of said access clock, an epochal time datum and an initial state datum to generate said access code.
- 16. An electronic lock comprising an access computer, an access clock having an output, an unlocking means controlled by said access computer, a means of reading an external memory, a power supply powering said access computer, said access clock and said unlocking means, an access memory operatively coupled to said access computer, said access memory storing a epochal datum, an initial state datum and an access code generating algorithm, said access computer using said epochal datum, said initial state datum and said output of said access clock as inputs to said algorithm, said algorithm generating an access code valid for a predetermined interval, said access computer reading said external memory during said predetermined interval and operating said unlocking means if a datum in said external memory matches said access code.
Specification