Chaos and DNA Blended Hybrid Encryption Algorithm for Secure Image Transmission over DCT Pre-coded OFDM

摘要

In this paper, a hybrid security solution based on the chaotic map for a discrete cosine transform (DCT) precoded orthogonal frequency division multiplexing (OFDM) system is proposed. The two-level encryption scheme is employed to encrypt the image in the upper and physical layer of the OFDM system. At first, bit-level encryption based on Deoxyribo Nucleic Acid coding and combined chaotic map is done in the upper layer of the proposed system. Then, the encrypted bitstreams are fed to the OFDM transmitter where the real and imaginary parts of the quadrature amplitude modulated symbols are scrambled chaotically to achieve the symbol level encryption in the physical layer of OFDM system. In addition to the hybrid security model, DCT precoding is added to achieve the trade-off between bit error rate (BER) and peak to average power ratio (PAPR) performance. Experiments are carried out to validate the strength of encryption algorithms against key sensitivity, statistical and differential attacks. Further, the BER, PAPR and peak signal to noise ratio performances have been analyzed for various cases to prove the strength of the proposed system to achieve enhanced security with better power and BER performance.