Patent attributes
The embodiments provide cryptography keys for communicating devices that are based on information known only to the devices. Each device determines the information without communicating key information related to the key with the other. In an implementation, a first device sends a first signal to a second device, the second device loops back the first signal to the first device as a second signal, and the first device generates a first key based on error information from the second signal. Also, the second device sends a third signal to the first device, the first device loops back the third signal to the first device as a fourth signal, and the second device generates a second key based on error information from the fourth signal. The first device and second device then encrypt and decrypt communications between the first device and second device using the first key and second key.
