Security system having randomized synchronization code after power up

A method, comprising the steps of:

• (a) powering up an integrated circuit;
• (b) causing a sequential state machine of said integrated circuit to transition through a first number of states to generate a first binary number;
• (c) using said first binary number to generate a first synchronization code and to output said first synchronization code onto an output terminal of said integrated circuit;
• (d) after step (c), generating a second binary number by causing said sequential state machine of said integrated circuit to transition a predetermined number of times;
• (e) using said second binary number to generate a verification code and to output said verification code onto said output terminal of said integrated circuit;
• (f) after steps (a) through (e), powering down said integrated circuit;
• (g) after step (f), powering up said integrated circuit;
• (h) after step (g), causing said sequential state machine to transition through a second number of states to generate a third binary number;
• and
• (i) using said third binary number to generate a second synchronization code and to output said second synchronization code onto said output terminal of said integrated circuit,
• wherein said sequential state machine comprises a first pseudo-random number generator and a second pseudo-random number generator, said method further comprising the steps of:
• (b1) after step (a) and before said first synchronization code is generated, loading said first pseudo-random number generator with a predetermined value;
• and
• (h1) after step (g) and before said second synchronization code is generated, loading said first pseudo-random number generator with said predetermined value;
• and
• wherein step (d) of generating a second binary number further comprises the steps of:
• causing said first pseudo-random number generator to transition to a new state;
• and
• causing said second pseudo-random number generator to transition to a new state.

A method of operation of a wireless security system, said security system comprising a mobile transmitting unit and a receiving unit, comprising:

• step for generating first synchronization code information in said transmitting unit after power is first supplied to said transmitting unit;
• step for transmitting said first synchronization code information from said transmitting unit to said receiving unit;
• in said transmitting unit, step for using said first synchronization code information to generate verification code information in accordance with an encryption method;
• in said receiving unit, step for using said first synchronization code information to generate reference code information exactly equal to said verification code information in accordance with said encryption method;
• step for transmitting said verification code information from said transmitting unit to said receiving unit;
• in said receiving unit, step for comparing said verification code information received from said transmitting unit with said reference code information generated in said receiving unit;
• and
• in said transmitting unit, step for generating and transmitting second synchronization code information different from said first synchronization code information after power is interrupted and then supplied to said transmitting unit a second time.

A transmitting unit for a wireless security system, comprising:

• a manually-operable switch;
• means having an input terminal and an output terminal, said input terminal being coupled to receive an activation signal from said switch, said means being for outputting a randomized synchronization code onto said output terminal after said means is powered up, said synchronization code being at least in part dependent on a timing of said activation signal, said means also being for outputting a rolling verification code onto said output terminal after said randomized synchronization code is output onto said output terminal;
• and
• a battery for providing power to said means for outputting.

A transmitting unit for a wireless security system, comprising:

• a manually-operable switch;
• an integrated circuit having an input terminal and an output terminal, said input terminal being coupled to receive an activation signal from said switch, said integrated circuit outputting a randomized synchronization code onto said output terminal after said integrated circuit is powered up a first time, said integrated circuit outputting a plurality of randomized rolling verification codes onto said output terminal after said randomized synchronization code is output but before said integrated circuit is powered up a second time;
• and
• a battery for providing power to said integrated circuit.

A method of operation of a transmitting unit for a wireless security system, comprising the steps of:

• (a) generating a synchronization code A in said transmitting unit after power is supplied to said transmitting unit a first time but before power is supplied a second time, said synchronization code A being the first synchronization code generated in said transmitting unit after power is supplied said first time;
• (b) generating a plurality of randomized rolling verification codes in said transmitting unit after step (a), each of said plurality of randomized rolling verification codes being generated by causing a sequential state machine to transition a respective predetermined number of states;
• and
• (c) generating a synchronization code B in said transmitting unit after power is supplied to said transmitting unit said second time, said synchronization code B being the first synchronization code generated in said transmitting unit after power is supplied said second time, said synchronization code B being different than said synchronization code A.