Implementation of El-Gamal algorithm for speech signals encryption and decryption

In the applications of Internet and wireless communication network, information security is one of the most challenging aspects. Cryptography is the best solution that offers the requisite protection from unintended persons. By using encryption and decryption mechanisms, cryptography can convert the data form its readable form to unreadable one so that only the intended receiver can read the message and alter it. By this way, one can ensure that message can be sent or stored without any modification. The presented work is concerned with a particular type of asymmetric key cryptography called El-Gamal algorithm to be used for speech signals encryption and decryption. First, the speech signal is encrypted by employing El-Gamal algorithm throughout encryption process at the sender and then transmitted to the particular recipient. Second, the recipient will recover the original signal throughout the decryption process. The cryptosystem performance is evaluated via different quality measures for audio signals encryption/decryption including Signal to Noise Ratio, Segmental Signal to Noise-Ratio and Log-Likelihood Ratio that are reach to -35.0224 dB, -38.0201 dB and 2.1145 respectively for the encrypted signal. The given results confirm the effectiveness of the presented scheme and robustness against noise effect.