SHAKE: SHared Acceleration Key Establishment for Resource-Constrained IoT Devices

IoT security for resource-constrained devices is largely based on symmetric block ciphers, such as AES. In such resource-constrained contexts, and particularly in the case of large-scale IoT deployments with multiple devices, the installation of encryption keys can pose a significant challenge. This paper presents SHAKE (SHared Acceleration Key Establishment): a convenient means to generate and install secret keys in IoT devices during deployment. Using SHAKE, an IoT deployment technician can generate and install a shared encryption key on two devices by holding them together and shaking them. SHAKE, operating on each of the devices, captures these movements from an on-board accelerometer and generates a secret key based on the shared acceleration profile. We provide a proof-of-concept implementation of SHAKE for the Contiki-NG operating system and assess its security against mimic attacks, that is the scenario whereby an eavesdropper with a clear line of sight to the deployment technician tries to mimic the random movements to generate the same key. Finally, we assess the energy requirements for generating a 128-bit key with SHAKE and we compare it against state-of-the-art methods for key generation.