Dissertation > Excellent graduate degree dissertation topics show

(k, n) and color visual secret sharing scheme and Its Application Research

Author: SuXiuNa
Tutor: ZhangJianHong
School: North China University of
Course: Applied Mathematics
Keywords: Halftone color model Cryptography visual Cryptography pixel expansion
CLC: TP309.7
Type: Master's thesis
Year: 2012
Downloads: 35
Quote: 0
Read: Download Dissertation

Abstract


As a kind of cryptography, Visual Cryptography encodes a secret image into several images, from which we can’t get any information. However, its decryption is completed directly by human’s visual system without any complicated mathematical calculation. So Visual Cryptography is a very good plan when we can’t use the computer decryption. The initial Visual Cryptography can only be applied to the binary image, accompanied by two big problems of pixel expansion and contrast loss. When Visual Cryptography is applied to grayscale images and color ones, pixel expansion and contrast loss problems have become worse and worse that they have a direct influence on the application of visual cryptography in real life. In this paper, we propose a new visual cryptographic method for chromatic images with no pixel expansion and less contrast loss. Here, we use the idea of multi-point encryption, taking m continuous points as encryption sequence each time to commit encryption. This could make sure that there must be b encryption sequences using fundamental matrix with blacks points and the other (m-b) ones are encoded with fundamental matrix with white points, in m encryption sequences with b black points each. Moreover, it ensures a regular transformation in the stacked image with black and white. We further analyze the values of m on the basis that pixel does not expand, and find that the contrast ratio loss of encryption result is the least when m equals2.For chromatic images, this paper uses the principle of color model to decompose an initial chromatic image into three monochromatic images of cyan, magenta, and yellow. Using halftone technology, we transform the three monochromatic images into three binary images, which are then encoded and decomposed into n share images separately with the multi-point encryption method. Finally, we overlap the i-th share image of each binary image into the i-th chromatic share image, and these n sheets will be assigned to n different participants. The experimental results prove that the method in this paper completely overcomes pixel expansion problem and share images have sufficient security. In visual effect aspect, the contrast ratio loss of encryption results is very small and the restoring images are also very clear, when the value of m is2.

Related Dissertations

  1. Guard Against Phishing Attacks for Two-way User Authentication Mechanisms and Implementation,TP393.08
  2. A Study of Watermarking Algorithm for Halftoning Image,TP309.7
  3. Constructions of Visual Cryptography Schemes with the Applications,TN918.1
  4. The Research on Design and Encoding Methods of Visual 2-d Barcode,TP391.44
  5. Research on Visual Cryptography Scheme for Cheating Prevention,TN918.2
  6. Research on Optimizing Parameters and Aspect Variant of Visual Cryptography,TN918.1
  7. The Research and Application of Image Segmentation on Document Image Watermarking,TP309.7
  8. Research and Optimize on Pixel Unexpanded and Threshold Visual Cryptography Scheme,TP393.08
  9. Research of Visual Cryptography and Its Application,TP309
  10. Research of Dot Diffusion Algorithm and Image Quality Assessment Based on HVS,TP391.41
  11. The Auto-transforming of Bitmap from True-color to Index-color and Researching on Dithering Technique,TN942
  12. Research on Digital Watermark Available for Printed Images,TP309
  13. Study on Information Hiding Technology Based on Halftone Screening Anti-counterfeit Printing,TP391.41
  14. A Error Diffusion Halftone Algorithm Based on Visual Error Feedback,TP391.41
  15. The Study of Watermarking Arithmetic for Halftone Image Based on Human Vision System Model,TS853
  16. Study on Lossless Compression Algorithms for Gray Halftone,TP391.41
  17. Research of Error Diffusion Algorithm Based on HVS Model,TP391.41
  18. An Improved Error Diffusion Algorithm,TP391.41
  19. The Research of Digital Watermarking Algorithm for Print-Scan Attack Process,TP309.7
  20. Cheating and Anti-Cheating in Visual Cryptography Scheme,TN918.1

CLC: > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > General issues > Security and confidentiality > Encryption and decryption
© 2012 www.DissertationTopic.Net  Mobile