Within the cooperative research project "LoRaKey" (FFG Bridge), the Institute of IT Security Research and Microtronics GmbH have explored novel ways of performing a secret key refreshment. The main outcomes of the project are described in the paper* “Experimental Investigation on Wireless Key Generation for Low Power Wide Area Networks” which was written in cooperation with the University of Liverpool and will be published in the IEEE Internet of Things journal (IF: 9.515). 

Extracting Secret Keys from Long-Range Wireless Communication

The renewal of the cryptographic key is one of the most important challenges the Internet of Things communication faces. In addition to cryptographic key exchange, a novel wireless secret key agreement method has gained popularity over the course of the last few years. In such concepts, the legitimate users extract secret keys from the random wireless channel characteristics.

However, previous works on the subject were likely to use local wireless network technologies. Therefore, the main focus of the project LoRaKey was on implementing the wireless secret key agreement for long-range wireless protocols such as LoRaWAN. By combining reconfigurable antenna concepts with suitable key generation software algorithms, the team achieved a key agreement over a distance of 7 km. According to the author's knowledge, this is the longest range reported for the key agreement implemented with the LoRaWAN technology to date. 

*An early-access online version of the paper is available at: https://ieeexplore.ieee.org/document/8865100.