A lossless digital encryption system for multimedia using orthogonal transforms

In this research work, we have developed a novel lossless digital encryption system for multimedia using the orthogonal transforms for the encryption of all types of image and audio formats. In addition, we have used the symmetric properties of the orthogonal transforms to calculate the inverse of the orthogonal matrices during the execution of the decryption process to speed up the operations and reduce the cost of performance. Several classical image encryption approaches such as Discrete Cosine Transform (DCT), Hadamard Transform (HT) as well as Malakooti Transform (MT), have been proposed and used. We also have proposed, a new Malakooti-Raeisi (MR) Key Gen Algorithm that can be used to encrypt and decrypt the voice signals by applying the XOR operation over the voice signals and Key Gen Sequences. The proposed Key Gen algorithm along with above orthogonal transforms have been used to increase the levels of security as well as the robustness of our algorithm during the image encryption/decryption process. We have encrypted/decrypted voice signals and a few images with only the M-R Key Gen values to show the ability of our algorithm for the encryption/decryption of both voice signals and images with a high accuracy and a reasonable security without using any other transforms. Our algorithm has a wide range of applications such as real time voice transmission, secure voice chat, and secure video encryption.