US Patent 11102203 Method of authenticating a device

A method of authenticating a second electronic device at a first electronic device, the method comprising: providing at the second electronic device a memory, the memory comprising a first memory portion which has restricted access and is readable only when a first secret key is presented to the second electronic device; sending the first secret key from the first electronic device to the second electronic device; in response, sending a second secret key stored in the first memory portion from the second electronic device to the first electronic device; and authenticating the second secret key at the first electronic device.