The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Simulation and the monte carlo method

Cosine-transform-based chaotic system for image encryption

[서평]「Digital Video Processing」

This paper proposes a new adaptive least-significant- bit (LSB) steganographic method using pixel-value differencing (PVD) that provides a larger embedding capacity and imperceptible stegoimages. The method exploits the difference value of two consecutive pixels to estimate how many secret bits will be embedded into the two pixels. Pixels located in the edge areas are embedded by a k-bit LSB substitution method with a larger value of k than that of the pixels located in smooth areas. The range of difference values is adaptively divided into lower level, middle level, and higher level. For any pair of consecutive pixels, both pixels are embedded by the k-bit LSB substitution method. However, the value k is adaptive and is decided by the level which the difference value belongs to. In order to remain at the same level where the difference value of two consecutive pixels belongs, before and after embedding, a delicate readjusting phase is used. When compared to the past study of Wu et al.'s PVD and LSB replacement method, our experimental results show that our proposed approach provides both larger embedding capacity and higher image quality.

Adaptive Data Hiding in Edge Areas of Images With Spatial LSB Domain Systems

In this paper, we shall propose a new image steganographic technique capable of producing a secret-embedded image that is totally indistinguishable from the original image by the human eye. In addition, our new method avoids the falling-off-boundary problem by using pixel-value differencing and the modulus function. First, we derive a difference value from two consecutive pixels by utilizing the pixel-value differencing technique (PVD). The hiding capacity of the two consecutive pixels depends on the difference value. In other words, the smoother area is, the less secret data can be hidden; on the contrary, the more edges an area has, the more secret data can be embedded. This way, the stego-image quality degradation is more imperceptible to the human eye. Second, the remainder of the two consecutive pixels can be computed by using the modulus operation, and then secret data can be embedded into the two pixels by modifying their remainder. In our scheme, there is an optimal approach to alter the remainder so as to greatly reduce the image distortion caused by the hiding of the secret data. The values of the two consecutive pixels are scarcely changed after the embedding of the secret message by the proposed optimal alteration algorithm. Experimental results have also demonstrated that the proposed scheme is secure against the RS detection attack.

(Journal of Systems and Software, 81(1):150-158)A high quality steganographic method with pixel-value differencing and modulus function

A high quality steganographic method with pixel-value differencing and modulus function

We present a high-capacity steganographic approach for three-dimensional (3D) polygonal meshes. We first use the representation information of a 3D model to embed messages. Our approach successfully combines both the spatial domain and the representation domain for steganography. In the spatial domain, every vertex of a 3D polygonal mesh can be represented by at least three bits using a modified multi-level embed procedure (MMLEP). In the representation domain, the representation order of vertices and polygons and even the topology information of polygons can be represented with an average of six bits per vertex using the proposed representation rearrangement procedure (RRP). Experimental results show that the proposed technique is efficient and secure, has high capacity and low distortion, and is robust against affine transformations. Our technique is a feasible alternative to other steganographic approaches.

A high-capacity steganographic approach for 3D polygonal meshes

Hiding data in spatial domain images with distortion tolerance

We present an efficient digital steganographic technique for three-dimensional (3D) triangle meshes. It is based on a substitutive blind procedure in the spatial domain. The basic idea is to consider every vertex of a triangle as a message vertex. We propose an efficient data structure and advanced jump strategy to fast assign order to the message vertex. We also provide a Multi-Level Embed Procedure (MLEP), including sliding, extending, and rotating levels, to embed information based on shifting the message vertex by its geometrical property. Experimental results show that the proposed technique is efficient and secure, has high capacity and low distortion, and is robust against affine transformations (which include translation, rotation, scaling, or their combined operations). The technique provides an automatic, reversible method and has proven to be feasible in steganography.

Chung-Ming Wang

Papers

(Journal of Systems and Software, 81(1):150-158)A high quality steganographic method with pixel-value differencing and modulus function

A high quality steganographic method with pixel-value differencing and modulus function

A high-capacity steganographic approach for 3D polygonal meshes

Hiding data in spatial domain images with distortion tolerance

An Efficient Information Hiding Algorithm for Polygon Models