Cryptosystem Based on the Elliptic Curve With a High Degree of Resistance to Damage on the Encrypted Images

In this work, a novel symmetric cryptosystem for image encryption is presented. The Symmetric Cryptosystem of the Elliptic Curve (SCEC) can resist damage to encrypted figures, up to 40% of the original figure. SCEC uses chaos to generate an $8\times {8}$ S-box with high nonlinearity to avoid the linear attack. A random permutation is used before starting encryption, making the cryptosystem more robust. For testing, damage according to four types of noise was applied to the encrypted images: additive, multiplicative, Gaussian, or occlusion. The median filter was applied to correct the damage in encrypted images, improving its sharpness, and a new measure, the Similarity Parameter (SP), is proposed to evaluate the difference between the original image and the decrypted image with damage. Several parameters and tests were applied to evaluate the performance of SCEC, from the encryption quality to the resistance to the differential attack. Experimental results indicate that SCEC has high-quality cryptographic properties, very much similar to the corresponding values of AES but with the addition of a high protection to noise damage on the encrypted images.