Platform for Digital Voice Communication with Channel-Based Key Generation

This paper proposes a novel method for the integration of channel-based key generation in a real-time digital voice communication system. For this purpose, a specific hardware platform was developed. To obtain the keys for the cipher, channel-based key generation is used to generate identical keys on both sides of the channel, based on the unique reciprocal channel characteristics. Hamming code key reconciliation drastically reduces the probability of remaining key errors, while a cyclic redundancy check (CRC) is used as a final checking mechanism. As a proof of concept, the generated key is used to encrypt as well as decrypt the audio by means of an XOR operation at both sides of the link. Several measurements were performed, showing that new keys are continuously being formed and replaced. Additional measurements also create more insight into the key update rate and key entropy for different parameter settings in the algorithm.