Discrete Cosine Transform-Based Key Generation Scheme for Indoor Environment

One of the widely used techniques to ensure confidentiality in the Internet of Things (IoT) communications is cryptography. The technique works by establishing a secure path for communication between IoT devices. However, the obstacle that occurs is that the IoT device is a device with computational limitations so that it is unable to implement the secret key distribution mechanism in the cryptographic technique. To overcome this problem, some researchers focus on efforts to generate a random secret key on each device by utilizing the randomness of the communication channel. This paper proposes a key generation scheme intended for IoT devices using IEEE 802.11. This scheme utilizes the Discrete Cosine Transform (DCT) method to increase the correlation coefficient of the observed communication channel and reduce the resulting secret key bit mismatch. Performance validation of the key generation scheme carried out in an indoor environment shows that the resulting scheme can increase the correlation coefficient up to 20% and achieve a BGR of up to 8.52488 bps.