Transmission of Chaotic-based Encrypted Audio Through OFDM

Nowadays, wireless communications play a vital role in all aspects in our daily life activities. A major part of such communications is audio and its rate increases dramatically. Securing audio during such communications is very important issue. Though OFDM is characterized by its strength against various broadcast impairments, the distinct time and frequency features makes signal of traditional OFDM vulnerable to malicious eavesdropping and intrusion. This paper proposes a communication model for encrypting and transmitting audio over OFDM systems. The 2D Baker, Logistic and Standard chaotic encryption schemes are utilized in the suggested model to encrypt and decrypt the transmitted audio. A simulation model for the proposed communication system is built using various encryption/decryption quality indicators to assess and compare its performance. The results demonstrate a good performance for the suggested communication model using all of the three studied chaotic encryption schemes. It also shows that the proposed communication mode is immune against noise distortion. One more noticed point from the result is that, the performance of the 2D Standard Map chaotic map in the proposed communication model is superior to that of the other two studied chaotic encryption schemes in terms of Spectral Distortion, Log Likelihood Ratio, Correlation Coefficient, Segmental Signal-to-Noise Ratio (SNRseg) and SNR encryption/decryption quality metrics.