Catálogo de publicaciones - libros

We present in this paper a new approach for universal JPEG steganalysis and propose studying statistics of the compressed DCT coefficients. This approach is motivated by the Avalanche Criterion of the JPEG lossless compression step. This criterion makes possible the design of detectors whose detection rates are independent of the payload. We design an universal steganalytic scheme using blocks of the JPEG file binary output stream. We compute higher order statistics over their Hamming weights and combined them with a Kullbak-Leibler distance between the probability density function of these weights and a benchmark one. We evaluate the universality of our detector through its capacity to efficiently detect the use of a new algorithm not used during the training step. To that goal, we examinate training sets produced by Outguess, F5 and JPhide-and-Seek. The experimental results we obtained show that our scheme is able to detect the use of new algorithms with high detection rate (≈90%) even with very low embedding rates (<10^− − 5).

In this paper, using a new steganalytic method, namely the left-and-right cube analysis (LRCA), we explore the steganography exploiting the JPEG2000 image as the carrier medium, where the steganography works by substituting message bits for the least significant bits (LSBs) of the quantized wavelet coefficients. For the achievement of the LRCA implementation on JPEG2000 images, we establish an appropriate sampling rule to extract the sample vectors from the image data, i.e., the quantized wavelet coefficients, in the wavelet domain. In experiments, we used the LSB steganography and the bit-plane complexity segmentation (BPCS) steganography in order to generate the stego images. In results, the proposed method works well for both steganographic methods, and outperforms some other previous steganalytic methods.

In 2005, Ginger Myles and Hongxia Jin proposed a software watermarking scheme based on converting jump instructions or unconditional branch statements (UBSs) by calls to a fingerprint branch function (FBF) that computes the correct target address of the UBS as a function of the generated fingerprint and integrity check. If the program is tampered with, the fingerprint and integrity checks change and the target address will not be computed correctly. In this paper, we present an attack based on tracking stack pointer modifications to break the scheme and provide implementation details. The key element of the attack is to remove the fingerprint and integrity check generating code from the program after disassociating the target address from the fingerprint and integrity value. Using the debugging tools that give vast control to the attacker to track stack pointer operations, we perform both subtractive and watermark replacement attacks. The major steps in the attack are automated resulting in a fast and low-cost attack.

To enable copyright protection and authentication, robust digital watermark can be embedded into multimedia contents imperceptibly. However, geometric distortions pose a significant threat to robust image watermarking because it can desynchronize the watermark information while preserving the visual quality. To overcome this, we developed an invariant domain with three transforms; Fast Fourier Transform (FFT), Log-Polar Mapping (LPM), and Dual Tree-Complex Wavelet Transform (DT-CWT). Shift invariance is obtained using FFT. Rotation and scaling invariance are achieved by taking the DT-CWT of a LPM output. Unlike most invariant schemes, our method eliminates explicit re-synchronization. The method resists geometric distortions at both global and local scales. It is also robust against JPEG compression and common image processing. In addition, it exploits perceptual masking property of the DT-CWT subbands, and its watermark detection step does not require the cover image. Experiment on a large set of natural images shows the robustness of the new scheme.

Till now, few desynchronization methods for video fingerprint have been presented, which are implemented in raw data. In this paper, a compression compliant video desynchronization method for collusion resilient fingerprint is proposed. The technique can simultaneously apply random space/time desynchronization and compression to videos. In our experiments, with little visual degradation, the joint process costs no more time and bandwidth than those of MPEG2 encoding/decoding. By this method, the video quality degrades dramatically for colluded copies. Besides evaluating the method by compression quality, compression time, and visual quality, we also discussed the system security. Two attacks are considered for the security evaluation: re-synchronization attack (including Most Similar Frame Collusion and Random Similar Frame Replacement) and re-desynchronization attack. Schemes for robustness to these attacks are also shown. Two theorems are presented to point out the security limit of single time desynchronization and single space desynchronization and the influence of related parameters to security.

This paper proposes a histogram shifting method for image lossless data hiding in integer wavelet transform domain. This algorithm hides data into wavelet coefficients of high frequency subbands. It shifts a part of the histogram of high frequency wavelet subbands and thus embeds data by using the created histogram zero-point. This shifting process may be sequentially carried out if necessary. Histogram modification technique is applied to prevent overflow and underflow. The performance of this proposed technique in terms of the data embedding payload versus the visual quality of marked images is compared with that of the existing lossless data hiding methods implemented in the spatial domain, integer cosine transform domain, and integer wavelet transform domain. The experimental results have demonstrated the superiority of the proposed method over the existing methods. That is, the proposed method has a larger embedding payload in the same visual quality (measured by PSNR (peak signal noise ratio)) or has a higher PSNR in the same payload.

In sensitive imagery, such as deep space exploration, military reconnaissance and medical diagnosis, traditional watermarks can be hardly found useful. The main reason is that the users are too worried about the loss of original information after the image being embedded with other data. Although early watermarking methods only distort the host signal imperceptibly, there is still some host information that may be permanently (irreversibly) lost. To avoid this disadvantage, some researchers (e.g. [1]-[3]) proposed the concept of reversible (lossless) watermark. Recently, more and more reversible watermarking methods have been proposed. However, the influence of [1]-[3] is obvious. In this paper, we focus on analyzing and comparing these three reversible watermarking methods. Our investigation covers several aspects including data hiding capacity, image quality, capacity resilience and control, computational complexity, security, and blind data extraction. Such analysis and comparison provide indispensable information for the design of new reversible watermarking techniques.

In this paper, we propose a reversible watermarking algorithm where an original image can be recovered from watermarked image data. Most watermarking algorithms cause degradation of image quality in original digital content in the process of embedding watermark. In the proposed algorithm, the original image can be obtained when the degradation is removed from the watermarked image after extracting watermark information. In the proposed algorithm, we utilize a peak point of image histogram and the location map and modify pixel values slightly to embed data. Because the peak point of image histogram and location map are employed in this algorithm, there is no need of extra information transmitted to receiving side. Also, because a slight modification on pixel values is conducted, highly imperceptibly images can be achieved. As locations of watermark embedding are identified using location map, amount of watermark data can dramatically increases through recursive embedding. Experimental results show that it can embed 5K to 130K bits of additional data.

We propose two efficient information hiding algorithms in the least significant bits of JPEG coefficients of images. Our algorithms embed information by modifying JPEG coefficients in such a way that the introduced distortion is minimized. We derive the expected value of the additional error due to distortion as a function of the message length and the probability distribution of the JPEG quantization errors of cover images. We have implemented our methods in Java and performed the extensive experiments with them. The experiments have shown that our theoretical predictions agree closely with the actual introduced distortions.

Digital watermarking is increasingly demanded for protecting or verifying the original image ownership. In this paper, we propose an improved differential energy watermarking using adaptive differential energy watermarking (ADEW) with cross binding wavelet tree (CBWT). The ADEW embeds a secret bit string which is obtained by the error correction code (ECC). Thus, the proposed method not only takes advantage of the ADEW’s error resilience but corrects a secret bit string by using ECC after error occurrence. Through experiments, we compare the proposed method with conventional DEW approaches and the proposed method shows the appropriateness for robust watermarking.