Abstract
The Internet and multimedia techniques, digital data such as texts, images, videos, and audios now have been widely used in our daily life. The security of the computer networks is insufficient, and the transmitted data could be intercepted or grabbed by an illegal user. Therefore, how to ensure the digital data to be securely transmitted via the Internet is an important issue. In this research paper we propose a new frequency domain method for image steganography. The merit is to increase image quality by hiding the messages in HL, LH, and HH sub-bands while keeping LL sub-band invariant. The advantage of this is that the original cover image does not have to be present on the receiver side. Therefore, the risk of disclosure of secret communication is lower and easily finds the patterns of artificial changes by comparing the original and stego object and provides the higher security then other because after embedded the secret data the cover image is encrypted using 32 bit key. we find the proposed algorithm support high capacity rate reach up to ¾ bits per pixel and that is form above 75% from the size of the input image cover file at SNR above 57 dB for the output signal. The proposed algorithm was implemented by using Matlab (2009a) programming. The proposed algorithm was tested using five cover image files: Airplane, Lena, Baboon, Papper and Girl. Each image has resolution of 8 bits per pixel and diamention is 256*256 pixel and text file is used in tests as secret messages. The quality of output signal in each test was computed using SNR and Time Complexity.