Abstract: The two important aspects of security that deal with transmitting information through some medium like internet are cryptography and Steganography. Cryptography deals with hiding the contents of a message and Steganography deals with hiding the presence of a message. In this paper, image is encrypted by ElGamal Algorithm and then encrypted image hide in other image for double tier security. For hiding the encrypted Image Modified LSB technique is used. The Modified LSB technique has more capacity as compared to LSB technique. Also in this paper MSE and PSNR of proposed Algorithm are compared with existing algorithm.

Keywords: ElGamal, Modified Least Significant bit (MLSB), Peak signal to Noise Ratio (PSNR), Mean Square Error (MSE), Encryption, Steganography.