Hiding a Secret Message Encrypted by S-DES Algorithm

Abstract

Nowadays, it is quite usual to transmit data through the internet, making safe online communication essential and transmitting data over internet channels requires maintaining its confidentiality and ensuring the integrity of the transmitted data from unauthorized individuals. The two most common techniques for supplying security are cryptography and steganography. Data is converted from a readable format into an unreadable one using cryptography. Steganography is the technique of hiding sensitive information in digital media including image, audio, and video. In our proposed system, both encryption and hiding techniques will be utilized. This study presents encryption using the S-DES algorithm, which generates a new key in each cycle to increases the complexity of the algorithm detection. An additional shared key between the sender and the receiver is added which is applied before starting the encryption process, that key must be hex-decimal in order to increase the level of security and give enough time to delay the guessing of the secret text by the attackers. The secret message data is concealed using one of the two techniques: either least significant bit (3-LSB) steganography or hiding in green and blue bits. To expedite the concealment process, the cover image is enhanced by applying a median filter, the median filter removes noise from the image while preserving its details. Finally, comparing the results of the two methods to determine which is better for the cover image in terms of PSNR metrics and hiding process time.