Color digital images are used in many important vital applications, and this digital image can be secret or it can be the carrier of highly confidential data that requires protection from the danger of tampering or intruders. Multiple methods are used to protect color digital images, the most important of which are encryption and decryption methods, and many of the methods used depend on standard methods.
Encryption methods based on standard algorithms are used to encrypt text messages and text files that are characterized by their small size, because these methods require a large time to implement the encryption and decryption process, which reduces their efficiency because the size of the digital image is often very large. In this paper, we will discuss a new method for encoding and decoding a digital image. This method will use a secret digital image as a key image that can be kept secretly without resorting to sending it, and it will be agreed upon between the sender and the receiver.
The image uses the key to generate a secret private key of the same size as the image to be encrypted to perform the necessary exclusions for encryption and decryption. In addition to the process of exclusion using the image key, the presented method implements the left-rotation operations for a specified number of digits (to be determined by the sender and in accordance with the receiver) in order to increase the degree of damage attached to the encrypted image to increase its distortion and make it completely incomprehensible.
The proposed method will be implemented using various images, and the practical results of this method will be compared with the results of the standard methods to show the extent to which the quality parameters (MSE, PSNR) and efficiency parameters (Encryption/decryption time, throughput) have been improved.