A PROPOSED METHOD COMBINING STEGANOGRAPHY AND CRYPTOGRAPHY WITHOUT MODIFYING THE COVER OBJECT

Abstract

Recent, it is very popular to use multimedia to communicate in digital age. Thus, protecting transfered data, especially confidential information, is an interested issue. Two methods to protect confidential data are encryption and steganography. Encryption algorithm converts a plaintext to a ciphertext and everyone only can decrypt it by the secret key. While steganography hides message into a cover object, this helps to protect the existence of message from attacker. To increasing security level, there are many methods combining steganography and cryptography to embed  ciphertext into the cover object. However, we can detect the difference between the stego object and the cover by analyzing histogram or PSNR value and embedded capacity is limited, which affects to imperceptibility. In this paper, we propose a new method combining steganography and cryptography to enhance embedded capacity without modifying the cover object.