Secure communications in a wireless system

In a communications system comprising a remote transmitting device and a receiving station having a receiver associated therewith, a method of configuring said receiver to register internally said transmitting device for subsequent encrypted data communications therewith, said method comprising the steps of:

• a) transmitting from said transmitting device to said receiver a first, unencrypted initialization message;
• b) storing at least a portion of said initialization message in memory at said receiver;
• c) transmitting to said receiver from said transmitting device a second message, wherein at least a portion of said message is in encrypted format;
• and
• d) verifying registration of said transmitting device with said receiver by utilizing at least part of said stored first message to decrypt said second message portion.

In a communications system comprising a plurality of remote transmitting devices and a receiving station having a receiver associated therewith, wherein said receiver has previously registered internally said transmitting devices for data communications therewith, a method of configuring said receiver to de-register all of said transmitting devices and temporarily disable subsequent encrypted data communications therewith pending re-registration of a transmitting device, said method comprising the steps of:

• a) configuring said receiving station and said transmitting device into a programming mode;
• b) transmitting to said receiver from one of said previously registered transmitting devices a first data message comprised of a command to delete all registration data from an internal memory table;
• c) deleting all registration data from said receiver internal memory table;
• and
• d) temporarily disabling said receiver from responding to further encrypted data messages.

In a communications system comprising a plurality of remote transmitting devices and a receiving station having a receiver associated therewith, wherein said receiver has previously registered internally said transmitting devices for data communications therewith, a method of configuring said receiver to de-register a selected one of said transmitting devices and temporarily disable subsequent encrypted data communications therewith pending re-registration of said transmitting device, said method comprising the steps of:

• a) configuring said receiving station and said transmitting device into a programming mode;
• b) transmitting to said receiver from a different one of said previously registered transmitting devices a first data message comprised of a command to delete the registration data associated with said selected device from an internal memory table;
• c) deleting said registration data from said receiver internal memory table;
• and
• d) temporarily disabling said receiver from responding to further encrypted data messages from said selected transmitting device.

A secure data communications system suitable for transmission of data messages, comprising:

• a) a plurality of remote transmitting devices for transmitting said data messages, each of said devices comprising:
• i) a random key generator for randomly generating data encryption keys, as a result of a command input by a user into said transmitting device, suitable for use in encrypting data messages prior to transmission;
• ii) a sequence number generator for keeping track of the transmission sequence number, said sequence number generator being incremented for each data transmission;
• iii) a memory for storing said randomly generated encryption key and a device identification code unique to said transmitting device;
• iv) means for encrypting data prior to transmission, said encrypting means utilizing said encryption key stored in memory;
• and
• v) transmitter means for transmitting a data message comprised of an encrypted data field, an unencrypted device identification field, and an encrypted sequence number field;
• and
• b) a receiving station comprising a data receiver for receiving said data messages from said transmitting devices, said receiver comprising:
• i) a memory table comprising a plurality of data records, each of said data records comprising a device identification code, an encryption key, and a transmission sequence number associated with one of said transmitting devices;
• ii) means for fetching from said memory table the data record associated with a data message received from a transmitting device by utilizing a device identification code from the received data message;
• iii) means for decrypting said sequence number from said received data message by using the encryption key fetched from memory;
• iv) means for comparing the decrypted received sequence number sequence number with said transmission sequence number sequence number fetched from memory;
• and
• v) means for allowing said received data message to be transmitted to a control unit associated with said receiver when the decrypted received sequence number sequence number and said transmission sequence number sequence number fetched from memory are within a predetermined range.

A remote transmitting device for transmitting data messages to a centrally located receiving station, said device comprising:

• a) a random key generator for randomly generating data encryption keys, as a result of a command input by a user into said transmitting device, suitable for use in encrypting data messages prior to transmission;
• b) a sequence number generator for keeping track of the transmission sequence number, said sequence number generator being incremented for each data transmission;
• c) a memory for storing said randomly generated encryption key and a device identification code unique to said transmitting device;
• d) means for encrypting data prior to transmission, said encrypting means utilizing said encryption key stored in memory;
• and
• e) transmitter means for transmitting a data message comprised of an encrypted data field, an unencrypted device identification field, and an encrypted sequence number sequence number field.