Multimedia Encryption on Bitplanes of Image Using ECC on Koblitz Curves with Lopez–Dahab Projective Coordinates

The requirements of video communication make people to use the Internet daily in their life. The security also plays a vital role to achieve smooth communication in multimedia. Multimedia encryption provides elegant solution to fulfill all these requirements. Among all public key encryption algorithms, elliptic curve cryptography (ECC) is attracted toward encryption of multimedia for better security with less bandwidth. We proposed a method named as perceptual encryption, which performs encryption on selective bitplanes of a grayscale image. The proposed method uses ECC on Koblitz curves with Lopez–Dahab projective coordinates to improve the efficiency of multimedia encryption and decryption. Moreover, scalar multiplication dominates the performance of ECC over Koblitz curves. The performance of Koblitz curves can be further improved by reducing number of field operations required at the time of point addition using Lopez–Dahab projective coordinates, anyway doubling needs less cost due to Frobenius endomorphism. Two parameters such as peak signal-to-noise ratio (PSNR) and structural similarity measure (SSIM) are considered to measure the quality of an image. The requirements of multimedia are analyzed based on the results obtained.