Image steganography based on combination of YCbCr color model and DWT

Steganography is the process of implanting secret message in a cover data without causing degradation neither to the cover information nor to the secret message implanted in the cover data. Most of the steganographic techniques are applied on images, texts, and protocols. In this paper a novel algorithm of image steganography is proposed to implant a secret text message into a cover image using YCbCr color space model and 2D Haar Discrete Wavelet Transform. In this proposed technique, input text in ASCII code is encrypted by AES what ensures, that the relative letter frequency of a plain text secret message will be disturbed. Proposed technique also solves conversion between color space models RGB and YCbCr in spite of modification in component Cb by the secret message. This step allows extracting of secret message without errors what is a very important characteristic, because change of only one bit causes extracting of different character. Performance of the proposed algorithm has been gauged by the peak signal to noise ratio (PSNR) and mean square error (MSE) for the stego image.