A data hiding method without specifying embedded positions for JPEG image

In this paper the authors propose a data hiding method for JPEG images that has a degree of freedom in selecting the hiding position and does not require a reference image or knowledge of the hiding position during extraction. In conventional methods, the position for the transform coefficients which hide the data must be specified beforehand, and that position must be known during extraction. The proposed method does not require specifying the hiding position beforehand and offers some freedom in selecting the hiding position. Therefore, a hiding position that is appropriate can be selected for each image and block to be sul jected to JPEG encoding. Given this, the proposed method can reduce image degradation and improve compression efficiency compared to the conventional methods. Moreover, because knowledge of the hiding position is not required during extraction, information management is thus simpler during extraction. The effectiveness of the proposed method is confirmed through simulations. (C) 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(11): 21-30, 2007; Published online in Wiley InterScience (www.interscience.wiley.com).