Security key holder

Claim 1

A system for releasing a key at a remote location, comprising: a decoder unit, said decoder unit comprising a key holder that holds the key, said key holder connected to a lock that prevents the key from being removed from said key holder, said lock coupled to a stepper motor that unlocks said lock to release the key, said stepper motor coupled to said lock such that said stepper motor must be sequenced through multiple angular steps of said stepper motor in order to unlock said lock; a microprocessor coupled to said stepper motor such that said microprocessor directly controls said stepper motor; and an encoder unit that sends a key release command to said decoder unit to release the key.

Claim 2

A system for releasing a key at a remote location, comprising: a decoder unit, said decoder unit comprising a key holder that holds the key, said key holder connected to a lock that prevents the key from being removed from said key holder, said lock coupled to a stepper motor that unlocks said lock to release the key, said stepper motor coupled to said lock such that said stepper motor must be sequenced through multiple angular steps of said stepper motor in order to unlock said lock; a microprocessor coupled to said stepper motor such that said microprocessor directly controls said stepper motor; and an encoder unit that sends a key release command to said decoder unit to release the key.

Claim 26

A method of controlling a lock of a decoder unit, comprising the steps of: (a) generating a release code, said release code comprising an error detection code; (b) selecting an encryption method for encrypting said release code, said encryption method selected based on a value of an encoder clock such that different encryption methods are selected at different selection times; (c) encrypting said release code using the encryption method selected in step (b) to produce an encrypted release code; (d) transmitting said encrypted release code to said decoder unit, said decoder unit comprising a decoder clock which must be synchronized with said encoder clock to within a synchronization window in order to decrypt and interpret said encrypted release code; and at the decoder unit: (e) receiving said encrypted release code transmitted in step (d), and attempting to decrypt the encrypted release code using a plurality of different decryption methods which correspond to a plurality of different values of the decoder clock, the step of attempting to decrypt comprising using said error detection code to determine whether each decryption attempt is successful; and (f) when a decryption attempt is successful, adjusting the decoder clock to correspond to the encoder clock.

Claim 27

A method of controlling a lock of a decoder unit, comprising the steps of: (a) generating a release code, said release code comprising an error detection code; (b) selecting an encryption method for encrypting said release code, said encryption method selected based on a value of an encoder clock such that different encryption methods are selected at different selection times; (c) encrypting said release code using the encryption method selected in step (b) to produce an encrypted release code; (d) transmitting said encrypted release code to said decoder unit, said decoder unit comprising a decoder clock which must be synchronized with said encoder clock to within a synchronization window in order to decrypt and interpret said encrypted release code; and at the decoder unit: (e) receiving said encrypted release code transmitted in step (d), and attempting to decrypt the encrypted release code using a plurality of different decryption methods which correspond to a plurality of different values of the decoder clock, the step of attempting to decrypt comprising using said error detection code to determine whether each decryption attempt is successful; and (f) when a decryption attempt is successful, adjusting the decoder clock to correspond to the encoder clock.

Claim 37

A method of controlling a lock, comprising the steps of: (a) providing a stepper motor that is mechanically coupled to at least a portion of said lock such that said stepper motor must be sequenced through a plurality of rotational steps in order to move said lock from a locked position to an unlocked position; (b) providing a microprocessor that is electrically connected to control lines of said stepper motor such that said stepper motor is controlled by said microprocessor without the use of a separate stepper motor controller device; and (c) generating a sequence of values at the output of said microprocessor to rotate a shaft of said stepper motor and unlock said lock.

Claim 38

A method of controlling a lock, comprising the steps of: (a) providing a stepper motor that is mechanically coupled to at least a portion of said lock such that said stepper motor must be sequenced through a plurality of rotational steps in order to move said lock from a locked position to an unlocked position; (b) providing a microprocessor that is electrically connected to control lines of said stepper motor such that said stepper motor is controlled by said microprocessor without the use of a separate stepper motor controller device; and (c) generating a sequence of values at the output of said microprocessor to rotate a shaft of said stepper motor and unlock said lock.

Claim 54

A method of providing encryption in messages transmitted from an encoder unit to a decoder unit, said encoder unit comprising an encryptor clock for selecting an encryption technique, said method comprising the steps of: (a) providing a plurality of decoder units, each decoder unit of said plurality having a respective decryptor clock, each decryptor clock being generally synchronized with said encoder clock during normal operation of the respective decoder unit; (b) generating a message at the encoder unit, said message including an address which uniquely identifies one decoder unit of said plurality of decoder units; (c) selecting an encryption method based on a current value of said encryptor clock; (d) encrypting at least a portion of said message using said encryption method, to thereby generate an encrypted message; (e) broadcasting said encrypted message from said encoder unit to said plurality of decoder units; and (f) at each respective decoder unit of said plurality of decoder units: (i) receiving said encrypted message; (ii) reading a decryptor clock value from the decryptor clock of the respective decoder unit and selecting a range of acceptable clock values therefrom; (iii) attempting to decrypt said encrypted message using a plurality of different decryption methods, each of said plurality of different decryption methods corresponding to a respective clock value within said range of acceptable clock values; (iv) upon successful decryption, of said encrypted message in step (iii), using the decryption method which produced said successful decryption to determine the encryptor clock value used in step (c) to select said encryption method; and (v) synchronizing the decryptor clock of the respective decoder unit using the encryptor clock value determined in step (iv).

Claim 55

A method of providing encryption in messages transmitted from an encoder unit to a decoder unit, said encoder unit comprising an encryptor clock for selecting an encryption technique, said method comprising the steps of: (a) providing a plurality of decoder units, each decoder unit of said plurality having a respective decryptor clock, each decryptor clock being generally synchronized with said encoder clock during normal operation of the respective decoder unit; (b) generating a message at the encoder unit, said message including an address which uniquely identifies one decoder unit of said plurality of decoder units; (c) selecting an encryption method based on a current value of said encryptor clock; (d) encrypting at least a portion of said message using said encryption method, to thereby generate an encrypted message; (e) broadcasting said encrypted message from said encoder unit to said plurality of decoder units; and (f) at each respective decoder unit of said plurality of decoder units: (i) receiving said encrypted message; (ii) reading a decryptor clock value from the decryptor clock of the respective decoder unit and selecting a range of acceptable clock values therefrom; (iii) attempting to decrypt said encrypted message using a plurality of different decryption methods, each of said plurality of different decryption methods corresponding to a respective clock value within said range of acceptable clock values; (iv) upon successful decryption, of said encrypted message in step (iii), using the decryption method which produced said successful decryption to determine the encryptor clock value used in step (c) to select said encryption method; and (v) synchronizing the decryptor clock of the respective decoder unit using the encryptor clock value determined in step (iv).

Claim 60

A method of synchronizing a first device with a second device, said first device having a first clock and said second device having a second clock, said method comprising the steps of: (a) reading a value from said second clock and using said value to select an encryption method; (b) encrypting a message at said second device using said encryption method, to thereby generate an encrypted message; (c) transmitting said encrypted message from said second device to said first device; (d) attempting to decrypt said encrypted message at said first device using a plurality of alternative decryption methods, to thereby identify said encryption method used in step (b); (e) based on the encryption method identified in step (d), determining said value of said second clock; and (f) setting said first clock to a value which corresponds to said value of said second clock determined in step (e).

Claim 61

A method of synchronizing a first device with a second device, said first device having a first clock and said second device having a second clock, said method comprising the steps of: (a) reading a value from said second clock and using said value to select an encryption method; (b) encrypting a message at said second device using said encryption method, to thereby generate an encrypted message; (c) transmitting said encrypted message from said second device to said first device; (d) attempting to decrypt said encrypted message at said first device using a plurality of alternative decryption methods, to thereby identify said encryption method used in step (b); (e) based on the encryption method identified in step (d), determining said value of said second clock; and (f) setting said first clock to a value which corresponds to said value of said second clock determined in step (e).