Super Encryption using Transposition-Hill Cipher for Digital Color Image

Research on cryptography in digital image continues to grow today. One of the most widely used cryptographic algorithms is Hill cipher. This method is widely applied in various cryptographic studies to decrypt data. Along with the development of technology cryptographic techniques must be developed to improve security. This study aims to improve the security of image delivery by combining the Hill cipher algorithm with column transposition method. The column transposition is applied first to randomize the image, then the Hill algorithm is applied to substitute the image value. The combination of randomization and substitution techniques produces super encryption techniques that are more resistant to various attacks. This is evidenced by the experiments conducted in this study based on the measurement of PSNR, MSE, SSIM, entropy and the encrypted image histogram. The proposed method is superior to the transposition method only, Hill cipher only and Hill cipher-transposition.