Secret Image Hiding and Sharing Based on the (t, n)-Threshold

This study proposes a new secret image sharing method based on the (t,n)-threshold. The sharing method is completed through three main steps: (1) quantizing the secret image, (2) generating n shadows from the quantized image, and (3) sharing the n shadows among n cover images. Our goal is both to attain good stego-image and secret image quality preservation effects and to limit the size of each shadow image down to 1/t of that of the secret image for convenient transmission and storage. In the first step, the secret image is divided into non-overlapping 4 × 4 blocks that are quantized according to the results of block testing. Each block, after the block testing procedure, is judged to be either a smooth block or a non-smooth one. Smooth blocks can be neatly restored after being hidden into the cover image, while non-smooth blocks can be somewhat lossy, but such modification is perceptually invisible. The second step is to apply Shamir's (t,n)-threshold, which uses a (t−1)-degree polynomial to generate n shadows so that the secret image can be restored from any t out of n shadows. The last step involves a modulo operation to hide the n shadows in n cover images. According to our experimental results, the PSNR values of the reconstructed secret images by our method center around 39 dB, outperforming other recent methods.

[1]  B. Dasarathy.  Image data compression - block truncation coding , 1995 .

[2]  Belur V. Dasarathy.  Image Data Compression: Block Truncation Coding (Btc) Techniques , 1995 .

[3]  Motoi Iwata,et al.  Digital Steganography Utilizing Features of JPEG Images , 2004 .

[4]  Ja-Chen Lin,et al.  Sharing and hiding secret images with size constraint , 2004, Pattern Recognit..

[5]  Kuo-Liang Chung,et al.  A novel SVD- and VQ-based image hiding scheme , 2001, Pattern Recognit. Lett..

[6]  Chin-Chen Chang,et al.  A steganographic method based upon JPEG and quantization table modification , 2002, Inf. Sci..

[7]  Jiri Fridrich.  A New Steganographic Method for Palette-Based Images , 1999, PICS.

[8]  Moni Naor,et al.  Visual Cryptography , 1994, Encyclopedia of Multimedia.

[9]  Adi Shamir,et al.  How to share a secret , 1979, CACM.

[10]  Chang-Chou Lin,et al.  Visual cryptography for gray-level images by dithering techniques , 2003, Pattern Recognit. Lett..

[11]  Yu-Chee Tseng,et al.  A secure data hiding scheme for binary images , 2002, IEEE Trans. Commun..

[12]  大野 義夫,et al.  Computer Graphics : Principles and Practice, 2nd edition, J.D. Foley, A.van Dam, S.K. Feiner, J.F. Hughes, Addison-Wesley, 1990 , 1991 .

[13]  Chang-Chou Lin,et al.  Secret image sharing with steganography and authentication , 2004, J. Syst. Softw..

[14]  Ja-Chen Lin,et al.  Image hiding by optimal LSB substitution and genetic algorithm , 2001, Pattern Recognit..

[15]  Ja-Chen Lin,et al.  Secret image sharing , 2002, Comput. Graph..

[16]  Hitoshi Kiya,et al.  A method of extracting embedded binary data from JPEG bitstreams using standard JPEG decoder , 2000, Proceedings 2000 International Conference on Image Processing (Cat. No.00CH37101).