Eiji Kawaguchi’s research while affiliated with Keio University and other places

Steganography is a technique to hide secret information in some other data (we call it a vessel) without leaving any apparent evidence of data alteration. This chapter describes a high capacity steganographic method called bit-plane complexity segmentation (BPCS) steganography. BPCS steganography usually uses an image as the vessel data, and secret information is embedded in the bit-planes of the vessel. This technique makes use of the characteristics of the human vision system whereby a human cannot perceive any shape information in a very complicated binary pattern. We can replace all of the “noise-like” regions in the bit-planes of the vessel image with secret data without deteriorating image quality. The principle and possible applications of BPCS, attacks to BPCS, and BPCS applicable to JPEG2000 images are here addressed. Additionally, histogram preserving JPEG steganography is described, and finally experimental results are given.

This paper presents two JPEG steganographic methods using quantization index modulation (QIM) in the discrete cosine transform (DCT) domain. The two methods approximately preserve the histogram of quantized DCT coefficients, aiming at secure JPEG steganography against histogram-based attacks. In comparison with F5 as a representative JPEG steganography, the proposed methods show high performance with regard to embedding rate, PSNR of stego image, and particularly histogram preservation. (c) 2005 Elsevier B.V. All rights reserved.

This paper presents two histogram preserving JPEG steganographic methods aiming at secure JPEG steganography against histogram-based attacks. The first one is a histogram quasi-preserving method, which uses quantization index modulation (QIM) at quantization step of DCT coefficients. Since a straightforward application of QIM causes a significant histogram change, a device is introduced in order not to change the after-embedding histogram excessively. The second one is a histogram preserving method based on histogram matching using two quantizers with a dead zone. In comparison with F5 as a representative JPEG steganography, the two methods show high performance with regard to embedding rate, PSNR of stego image, and particularly histogram preservation.

The abstract should summarize the contents of the paper and should Steganography is a technique to hide secret information in some other data (we call it a vessel) without leaving any apparent evidence of data alteration. All of the traditional steganographic techniques have limited information-hiding capacity. This is because the principle of those techniques was either to replace a special part of the frequency components of the vessel image, or to replace all the least significant bits of a multi-valued image with the secret information. Our new steganography uses an image as the vessel data, and we embed secret information in the bit-planes of the vessel. This technique makes use of the characteristics of the human vision system whereby a human cannot perceive any shape information in a very complicated binary pattern. We can replace all of the “noise-like” regions in the bit-planes of the vessel image with secret data without deteriorating the image quality. We termed our steganography “BPCS-Steganography,” which stands for Bit-Plane Complexity Segmentation Steganography.

Today, there is high demand for digital media archives that can archive wide variety of academic resources and deliver customized contents upon audiences' needs. Key challenges of the digital media archives for academic resources are a) a methodology to embed academically meaningful interpretation of resources, i.e. metadata, to digital media data themselves b) search mechanism to such academic metadata, and c) sophisticated access methodology to such digital archives. In this position paper, we describe our approach to these challenges, and how we're going to implement the digital media archives in our project.

Certificate documents today are either written or printed matter on a paper surface or plastic card. No digital data are accepted as a certificate document. People always asked to send an original certificate documents by traditional post mail even in this developing information age. The present paper proposes an unforgeable certificate document system wherein each document has a forgery-protective capability by itself. It does not need any communication with an authentication bureau. The system has several variations according to the key usage and additionally incorporated data. If this system is implemented, all certificate documents may be digitalized.

This paper presents a steganography method using lossy compressed video which provides a natural way to send a large amount of secret data. The proposed method is based on wavelet compression for video data and bit-plane complexity segmentation (BPCS) steganography. In wavelet-based video compression methods such as 3-D set partitioning in hierarchical trees (SPIHT) algorithm and motion-JPEG2000, wavelet coefficients in discrete wavelet transformed video are quantized into a bit-plane structure and therefore BPCS steganography can be applied in the wavelet domain. 3-D SPIHT-BPCS steganography and motion-JPEG2000-BPCS steganography are presented and tested, which are the integration of 3-D SPIHT video coding and BPCS steganography and that of motion-JPEG2000 and BPCS, respectively. Experimental results show that 3-D SPIHT-BPCS is superior to motion-JPEG2000-BPCS with regard to embedding performance.

This paper discusses an attack to BPCS-Steganography (Bit-Plane Complexity Segmentation-Steganography) and presents a countermeasure. BPCS is an image-based steganographic method. BPCS embeds secret data by replacing blocks that appear noise-like on bit-planes. Blocks on bit-planes are categorized as a "noise-like region" or an "informative region" by means of the binary-image feature called complexity. When the complexity distribution of noise-like blocks is different from the complexity distribution of the secret data that replaces those blocks, we can see an unusual shape in the form of a valley in the complexity histogram that represents the relative frequency of occurrence of the various complexities. This would be a signature of BPCS. Because steganography must hide the existence of the secret message, the signature should be removed from steganographic images. We present a method for making embedded binary patterns that quasipreserves the complexity distribution.

This paper presents a steganography method using lossy compressed video which provides a natural way to send a large amount of secret data. The proposed method is based on wavelet compression for video data and bit-plane complexity segmentation (BPCS) steganography. BPCS steganography makes use of bit-plane decomposition and the characteristics of the human vision system, where noise-like regions in bit-planes of a dummy image are replaced with secret data without deteriorating image quality. In wavelet-based video compression methods such as 3-D set partitioning in hierarchical trees (SPIHT) algorithm and Motion-JPEG2000, wavelet coefficients in discrete wavelet transformed video are quantized into a bit-plane structure and therefore BPCS steganography can be applied in the wavelet domain. 3-D SPIHT-BPCS steganography and Motion-JPEG2000-BPCS steganography are presented and tested, which are the integration of 3-D SPIHT video coding and BPCS steganography, and that of Motion-JPEG2000 and BPCS, respectively. Experimental results show that 3-D SPIHT-BPCS is superior to Motion-JPEG2000-BPCS with regard to embedding performance. In 3-D SPIHT-BPCS steganography, embedding rates of around 28% of the compressed video size are achieved for twelve bit representation of wavelet coefficients with no noticeable degradation in video quality.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.