Abstract
Recently, speech encryption attracts many researchers because of the various applications of speech communications such as; e-learning, e-banking, military, teleconferencing and other fields. In this work, a new modification on RSA (Rivest-Shamir-Adleman) algorithm is proposed to enhance the performance of conventional RSA up on application in audio cryptosystems. This paper is concerned with speech encryption and decryption based on the well-known RSA algorithm and some of its variants, including our own suggestion. The performance of both the original RSA algorithm and its variants is investigated and tested through estimating some parameters that give the indication of audio cryptography quality. The parameters that are estimated in the experimental test are; mean square error between the original signal and the decrypted signal, linear predictive code measure (LPC), cepstral distance measure (CD), the segmental signal-to-noise ratio (SSNR) and the execution time. Based on the estimated parameters, a performance comparison between the investigated algorithms is introduced. The obtained results show that the RSA algorithm and its variants are efficient to secure the audio communications and our new proposed modification reduces the processing time approximately by 39%-53%, compared to the original RSA algorithm and hence it is efficient in real time applications.