Color Image Encryption by Code Image and Hill Algorithm
Ali Moradmard · International Journal of Intelligent Information Systems · 2014
Today in a digital world, protection of information plays an essential role in message exchange and trading. Encryption is used to meet the security needs of safe transaction. Regarding the importance of the issue and the shift of traditional stage to digital stage, familiarity with encryption methods seems necessary. Different data have different methods of encryption. Images are also one type of data for which encryption is critically needed to prevent impermissible access. In this article, first a primary image is selected, then, based on the proportion of the image needing encryption, pixels from code image are picked and is being encrypted by a function. In the next stage, this proportion is being XOR-ed by the pixel proportion of the image needing encryption, and eventually the final proportion is encrypted by Hill Algorithm. MATLAB software has been used for studying the project, and efficiency of this method, in comparison to Hill Algorithm as a standard algorithm, is investigated. At the end, maintaining the image quality after decryption is evaluated by standards such as PSNR and SSID. The results indicate high efficiency of this method.