A secure scheme to share secret color images
ABSTRACT The main goal of this work is to study how discrete dynamical systems can be used to design secret sharing schemes. Specifically, the proposed scheme permits to share secret color images, and it is based on bidimensional cellular automata. The main idea is to analyze how a simple reversible model of computation allows one to compute the shares and then using the reverse computation in order to recover the secret image. Moreover, the proposed scheme exhibits good statistical properties.
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ABSTRACT: A practical specific (r, n) threshold scheme for secret digital images is proposed in this paper. By this scheme, we divide a secret digital image into n pieces and distribute them to n participants. The secret digital image can be reconstructed when and only when r or more participants cooperate for it. The time complexity of this proposed scheme is independent of the size of the secret image. In this scheme, the setup phase is bounded by i × j × ⌊r − 1/2⌊ + 2 module multiplications plus i × j × (r − 1) module additions, where i × j is the size of the codebook, except the time needed for generating the codebook. The reconstructing phase is bounded by O(r log2r). This scheme also achieves perfect secrecy.Inf. Sci. 01/1998; 111:335-345.
Article: Visual cryptography for color images[show abstract] [hide abstract]
ABSTRACT: Visual cryptography, an emerging cryptography technology, uses the characteristics of human vision to decrypt encrypted images. It needs neither cryptography knowledge nor complex computation. For security concerns, it also ensures that hackers cannot perceive any clues about a secret image from individual cover images. Since Naor and Shamir proposed the basic model of visual cryptography, researchers have published many related studies. Most of these studies, however, concentrate on binary images; few of them proposed methods for processing gray-level and color images. This paper proposes three methods for visual cryptography of gray-level and color images based on past studies in black-and-white visual cryptography, the halftone technology, and the color decomposition method. Our methods not only retain the advantages of black-and-white visual cryptography, which exploits the human visual system to decrypt secret images without computation, but also have the backward compatibility with the previous results in black-and-white visual cryptography, such as the t out of n threshold scheme, and can be applied to gray-level and color images easily.Pattern Recognition. 01/2003;
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ABSTRACT: Visual cryptography is a cryptographic paradigm introduced by Naor and Shamir [Lecture Notes in Comput. Sci., Vol. 950, Springer, Berlin, 1995, p. 1]. Some predefined set of participants can decode a secret message (a black and white image) without any knowledge of cryptography and without performing any cryptographic computation: Their visual system will decode the message.In this paper we define and analyze visual cryptography schemes for grey level images whose pixels have g grey levels ranging from 0 (representing a white pixel) to g−1 (representing a black pixel). Moreover, we give a necessary and sufficient condition for such schemes to exist.Information Processing Letters. 01/2000;