Medical JPEG image steganography based on preserving inter-block dependencies

Considering that traditional image steganography technologies suffer from the potential risk of failure under lossy channels, an enhanced adaptive steganography with multiple robustness against image processing attacks is proposed, while maintaining good detection resistance. First, a robust domain constructing method is proposed utilizing robust element extraction and optimal element modification, which can be applied to both spatial and JPEG images. Then, a robust steganography is proposed based on “Robust Domain Constructing + RS-STC Codes,” combined with cover selection, robust cover extraction, message coding, and embedding with minimized costs. In addition, to provide a theoretical basis for message extraction integrity, the fault tolerance of the proposed algorithm is deduced using error model based on burst errors and decoding damage. Finally, on the basis of parameter discussion about robust domain construction, performance experiments are conducted, and the recommended coding parameters are given for lossy channels with different attacks using the analytic results for fault tolerance. A series of experimental results demonstrate that the proposed algorithm can extract embedded messages with significantly higher accuracy after different attacks, such as compression, noising, scaling and other attacks, compared with the state-of-the-art adaptive steganography, and robust watermarking algorithms, while maintaining good detection resistant performance.

Multiple Robustness Enhancements for Image Adaptive Steganography in Lossy Channels

This paper proposes a framework to improve the existing distortion functions designed for JPEG steganography, which results in a better capability of countering steganalysis. Different from the existing steganography approach that minimizes image distortion, we minimize the feature distortion caused by data embedding. Given a JPEG image, we construct a reference image close to the image before JPEG compression. Guided by both the reference image and the feature distortion minimization, the state-of-the-art distortion functions designed for syndrome trellis coding embedding are improved by distinguishing the embedding costs for +1 versus −1 embedding. This paper has three contributions. First, the proposed framework outperforms the traditional, since we use the constructed reference image and the public steganalytic knowledge for data embedding. Second, the proposed framework is universal for improving distortion functions that were designed for JPEG steganography. Finally, experimental results also prove that the proposed approach has a better undetectability when examined by modern steganalytic tools.

On Improving Distortion Functions for JPEG Steganography

This letter proposes a batch steganographic method, which combines cover-selection and payload-allocation by steganographic distortion optimization. We first proved that with the value of payload increasing, the first-order derivative of steganographic distortion of a single cover is monotonically increasing. Then, we deduced that the first-order derivative of steganographic distortion of covers that selected from a given set should be equal if the total steganographic distortion of the corresponding selected covers is minimal. Finally, an algorithm was designed to combine cover-selection and payload-allocation, so that the optimal stego-covers can be obtained. Experiment results show that the undetectability is obviously improved when using the proposed steganographic method.

Joint Cover-Selection and Payload-Allocation by Steganographic Distortion Optimization

Recent studies have shown that the non-additive distortion model of Decomposing Joint Distortion ($DeJoin$) can work well for spatial image steganography by defining joint distortion with the principle of Synchronizing Modification Directions (SMD). However, no principles have yet produced to instruct the definition of joint distortion for JPEG steganography. Experimental results indicate that SMD can not be directly used for JPEG images, which means that simply pursuing modification directions clustered does not help improve the steganographic security. In this paper, we inspect the embedding change from the spatial domain and propose a principle of Block Boundary Continuity (BBC) for defining JPEG joint distortion, which aims to restrain blocking artifacts caused by inter-block adjacent modifications and thus effectively preserve the spatial continuity at block boundaries. According to BBC, whether inter-block adjacent modifications should be synchronized or desynchronized is related to the DCT mode and the adjacent direction of inter-block coefficients (horizontal or vertical). When built into $DeJoin$, experiments demonstrate that BBC does help improve state-of-the-art additive distortion schemes in terms of relatively large embedding payloads against modern JPEG steganalyzers.

Defining Joint Distortion for JPEG Steganography

A hybrid distortion function for JPEG steganography exploiting block fluctuation and quantization steps is proposed. To resist multidomain steganalysis, both spatial domain and discrete cosine transformation (DCT) domain are involved in the proposed distortion function. In spatial domain, a distortion value is allotted for each 8×8 block according to block fluctuation. In DCT domain, quantization steps are employed to allot distortion values for DCT coefficients in a block. The two elements, block distortion and quantization steps, are combined together to measure the embedding risk. By employing the syndrome trellis coding to embed secret data, the embedding changes are constrained in complex regions, where modifications are hard to be detected. When compared to current state-of-the-art steganographic methods for JPEG images, the proposed method presents less detectable artifacts.

Hybrid distortion function for JPEG steganography

The invention brings forward a method for transmitting secret information through a social network. The method enables secret transmission of data without influencing user usage. The method includes adata encryption step, an information hiding embedding step, an information hiding extraction step and data decryption phase. The method is characterized by encrypting the secret information to be transmitted first and then determining how to operate the information in the social network according to the encrypted information so as to enable secret transmission of the data. The method of the invention can satisfy the need of using the social network of the user and simultaneously enable covert communication. The method of the invention enables any amount of data to be transmitted. If the sizeof the data is different, the transmission efficiency of the data is different.

Yin Zhaoxia

Papers

Hybrid distortion function for JPEG steganography

A method for transmitting secret information through a social network