Abstract: A new method for hiding secret information in color images is proposed, in which bit planes are treated as binary images. A set of rules is used to check boundary pixels in the bit planes for data embedding eligibility. These rules can ensure correct extraction of the secret data from the stego-image without any other additional information. A key is introduced in identifying the eligible embedding positions to enhance security. Experiments show that, at an embedding rate of 1.5 bits per color pixel, the stego-images have no perceptual and histogram abnormality with PSNR values greater than 40 dB, and can resist several effective methods for steganalytical detection, achieving a good trade-off between security and embedding capacity.

Key words: steganography, color image, binary image