Design and implementation on FPGA of a real-time secure audio communication system

In communication systems, data transmitted over networks must be protected against access by unauthorized parties. Indeed, existing audio systems are based on classical cryptographic algorithms. However, the reliability of some of these algorithms is no longer guaranteed, and others need significant resources with regard to memory, energy, and computation time, making them unsuitable for resource-constrained boards. To rise to these challenging issues, this paper develops a secure real-time audio communication architecture based on chaotic systems. This architecture is implemented on a Nexys FPGA board. The encryption scheme undergoes two consecutive stages of confusion and diffusion. Statistical results confirm the robustness of the proposed encryption scheme against many attacks based on the NIST test, key sensitivity, key size, information entropy, and statistical analysis. The implementation results include 21% of logic elements and 0.43 W of dynamic power to carry out the desired functions. The proposed scheme can reach a maximum frequency of 254.38 MHz. Compared to related work, this paper proposes a lightweight encryption system able to be implemented in different resource-constrained hardware boards. In addition, the proposed solution covers the entire life cycle of an audio communication system, including audio acquisition, filtering, encryption/decryption, and data sending/receiving over WiFi. These features guarantee the successful use of this solution in audio communications systems.