Secret key programming technique for transponders using encryption

A base station for programming a secret key into a key transponder, wherein said key transponder stores a fixed ID, a first default key segment stored in a first memory page, and a second default key segment stored in a second memory page, and wherein said secret key comprises a first new secret key segment to be stored in said first memory page of said key transponder and a second new secret key segment to be stored in said second memory page of said key transponder, said base station comprising:

• a transceiver for wirelessly communicating with said key transponder;
• and
• a controller programmed to perform the steps of:
• conducting a mutual authentication process using a first default key segment and a second default key segment;
• sending a first write command identifying said first memory page;
• checking for a first acknowledgement signal from said key transponder;
• if said first acknowledgement signal is not detected, then returning to said step of conducting a mutual authentication process using said first default key segment and said second default key segment;
• if said first acknowledgement signal is detected, then sending a first read command identifying said first memory page;
• if no read data is detected in response to said first read command, then returning to said step of conducting a mutual authentication process using said first default key segment and said second default key segment;
• if correct read data is detected in response to said first read command, then sending a second write command identifying said second memory page;
• checking for a second acknowledgement signal from said key transponder;
• if said second acknowledgement signal is not detected, then conducting a mutual authentication process using said first new secret key segment and said second default key segment and returning to said step of sending a second write command;
• if said second acknowledgement signal is detected, then sending a second read command identifying said second memory page;
• if no read data is detected in response to said second read command, then returning to said step of conducting a mutual authentication process using said first new secret key segment and said second default key segment;
• if correct read data is detected in response to said second read command, then said base station associating said fixed ID of said key transponder with said first and second new secret key segments.

A method of programming a secret key into a key transponder from a base station, wherein said key transponder stores a fixed ID, a first default key segment stored in a first memory page, and a second default key segment stored in a second memory page, and wherein said secret key comprises a first new secret key segment to be stored in said first memory page of said key transponder and a second new secret key segment to be stored in said second memory page of said key transponder, said method comprising the steps of:

• conducting a mutual authentication process using a first default key segment and a second default key segment;
• sending a first write command identifying said first memory page;
• checking for a first acknowledgement signal from said key transponder;
• if said first acknowledgement signal is not detected, then returning to said step of conducting a mutual authentication process using said first default key segment and said second default key segment;
• if said first acknowledgement signal is detected, then sending a first read command identifying said first memory page;
• if no read data is detected in response to said first read command, then returning to said step of conducting a mutual authentication process using said first default key segment and said second default key segment;
• if any return data is detected in response to said first read command, then sending a second write command identifying said second memory page;
• checking for a second acknowledgement signal from said key transponder;
• if said second acknowledgement signal is not detected, then conducting a mutual authentication process using said first new secret key segment and said second default key segment and returning to said step of sending a second write command;
• if said second acknowledgement signal is detected, then sending a second read command identifying said second memory page;
• if no read data is detected in response to said second read command, then returning to said step of conducting a mutual authentication process using said first new secret key segment and said second default key segment;
• if any return data is detected in response to said second read command, then conducting said mutual authentication process using said first and second new secret key segments and if successful then said base station associating said fixed ID of said key transponder with said first and second new secret key segments.