关键词: 图像加密, 信息隐藏, 混沌理论, 差异扩展, 整数变换

Abstract: Aiming at the problems of traditional reversible information hiding algorithms such as declining quality of the host image, low security, and extra overhead for information recovery, a reversible information hiding algorithm combining chaos theory and integer transform is proposed. The carrier image is divided into sub-blocks of size 2×2 and their pixels are divided into labeled pixels and hidden pixels. The sub-block pixels are evened and expanded to obtain the difference values with the base pixels. If the extended pixel and the difference value satisfy a given threshold condition, the chaotic encrypted hidden information is transformed into the least significant bit of the concealed position pixel of the carrier sub-block by integer transform. Otherwise, the mark position pixel is odd-numbered and the least significant bit of the original pixel is recorded. The simulation test shows that the proposed hiding method can achieve the lossless restoration of the carrier image and the original image, which not only reduces the transmission load effectively, but also has high security.

Key words: image encryption, information hiding, chaos encryption, differential expansion, integer transformation