On Real-valued Visual Cryptographic Basis Matrices

Buckley, N and Nagar, Atulya K. and Arumugam, Subramanian (2016) On Real-valued Visual Cryptographic Basis Matrices. Journal of Universal Computer Science, 21. pp. 1536-1562. ISSN 0948-6968

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Visual cryptography (VC) encodes an image into noise-like shares, which can be stacked to reveal a reduced quality version of the original. The problem with encrypting colour images is that they must undergo heavy pre-processing to reduce them to binary, entailing significant quality loss. This paper proposes VC that works directly on intermediate grayscale values per colour channel and demonstrates real-valued basis matrices for this purpose. The resulting stacked shares produce a clearer reconstruction than in binary VC, and to the best of the authors’ knowledge, is the first method posing no restrictions on colour values
while maintaining the ability to decrypt with human vision. Grayscale and colour images of differing entropies are encrypted using fuzzy OR and XOR, and their PSNR and structural similarities are compared with binary VC to demonstrate improved quality. It is compared with previous research and its advantages highlighted, notably in high quality reconstructions with minimal processing.

Item Type: Article
Additional Information and Comments: Buckley, N., Nagar, A.K., Arumugam, S. (2016) On real-valued visual cryptographic basis matrices. Journal of Universal Computer Science, 21(12), pp.1536-1562. Available from: http://www.jucs.org/jucs_21_12/on_real_valued_visual/jucs_21_12_1536_1562_buckley.pdf
Keywords: visual cryptography; secret sharing; cryptanalysis; colour images; image processing
Faculty / Department: Faculty of Science > Mathematics and Computer Science
Depositing User: Matt Butler
Date Deposited: 21 Jan 2016 11:06
Last Modified: 21 Jan 2016 11:06
URI: https://hira.hope.ac.uk/id/eprint/692

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