Application of bit-plane decomposition steganography to progressively compressed data

摘要

Media data such as still image data is subjected to a wavelet transform, and then the wavelet coefficients are quantized. Bit-planes are prepared for the quantized wavelet coefficients. Confidential information is embedded into the bit-planes by using bit-plane decomposition steganography. The modified quantized wavelet coefficients are prepared based on the bit-planes into which the confidential information is embedded. Entropy encoding is performed on the modified quantized wavelet coefficients. As a result, the information is hidden in the media data subjected to progressive compression. On the other hand, entropy decoding is performed on the compressed data, into which the confidential information is embedded, to obtain quantized wavelet coefficients. A bit-plane structure is obtained from the quantized wavelet coefficients, and the hidden information is extracted from the bit-plane structure. In data communication using the compressed data, a third person is not aware of the presence of the hidden information, so that the security thereof can be enhanced. The bit-plane decomposition steganography becomes applicable to compressed data and is improved in the convenience and safety of its utilization.