In the last few years, we have seen many new and powerful steganography and steganalysis techniques reported in the literature. In the following tutorial we go over some general concepts and ideas that apply to steganography and steganalysis. We review and discuss the notions of steganographic security and capacity. Some of the more recent image steganography and steganalysis techniques are analyzed with this perspective, and their contributions are highlighted.

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Image Steganography: Concepts and Practice

Hiding secret data in images via predictive coding

Steganography - the art and science of hiding information has received much attention in the recent years. It can also be defined as the study of invisible communication that usually involves communication of secret data in an appropriate carrier, e.g., image, audio, video or TCP/IP header file. Many different carrier file formats can be used, but digital images are the most popular because of their frequency on the Internet. The main goal of steganography is to ensure that the transmitted message is completely masked, thereby ensuring that the message is accessible only to the intended receiver and does not attract attention from eavesdroppers and attackers. This paper is an attempt to study the various techniques use in steganography and provide a general overview of different algorithms of image steganography. There exists a large variety of steganography techniques

Image steganography techniques: an overview

This paper presents an improved image steganography scheme based on absolute moment block truncation coding (AMBTC). The purpose of the proposed scheme is to achieve high payload, good visual quality and low computation complexity at the same time. In the scheme, a threshold is predefined to classify the blocks of the AMBTC-compressed codes as smooth or complex blocks, in which data are then embedded. For the smooth blocks, the bit planes of them are used to embed the data. Later, the two quantization levels in the smooth block are re-calculated to minimize the distortion in image quality. For the complex blocks, a proportion of secret bits are concealed by exchanging the order of two quantization levels with together toggling the bit plane, by which the payload can be increased without any distortion. Furthermore, the proposed scheme inherits the advantages of the AMBTC method, such as pleasing image quality, ease to be implemented and low computational complexity. With adjustable threshold, the application of the proposed scheme becomes flexible, that means different thresholds can be used for different applications. Experimental results and analysis demonstrate the effectiveness and superiority of the proposed scheme.

High payload image steganography with minimum distortion based on absolute moment block truncation coding

A large number of commercial steganographic programs use the least significant bit embedding (LSB) as the method of choice for message hiding in 24-bit, 8-bit color images, and grayscale images respectively. It is commonly believed that changes to the LSBs of colors cannot be detected due to noise that is always present in digital images (J. Fridrich, et al., Oct. 2001). In this paper, we describe the LSB insertion technique, the discrete cosine transform (DCT) insertion technique is described and finally we propose a new technique that uses the idea of inserting a bit in the spatial domain combined with the DCT insertion technique

A robust steganography technique using discrete cosine transform insertion

We present a new steganographic technique for covert communications. The technique embeds the hidden information in the DFT domain after permuting the image pixels in the spatial domain using a key. The permutation process introduces randomness into the cover image and results in a significant increase in the number of transform coefficients that can be used to transmit the hidden information. The hidden information is embedded using a quantization technique. The perceptual and statistical properties of the cover and the stego images remain similar for small quantization steps. The security of the system is examined against known stego attack.

F. Alturki

Papers

Secure blind image steganographic technique using discrete Fourier transformation