Bit-level based secret sharing for image encryption

Rastislav Lukac, Konstantinos N. Plataniotis

Presented by Du-Shiau Tsai

Pattern Recognition 38 (2005) 767 – 772

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ContentsContents

1. Introduction 2. Visual Cryptography3. The proposed scheme4. Experiment results5. Conclusions

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IntroductionIntroduction

Secret image sharing (Tsai)

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IntroductionIntroduction

Classification of SIS (Tsai)

SIS

visual Cryptography(1994)

variant visual secret sharing(2000)

interpolation method (2002)

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IntroductionIntroduction

Visual cryptography is a secret sharing procedure for image data

Recover the secret by the human visual systemWithout additional computations and any knowledge of cryptography .

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IntroductionIntroductionUnfortunately, visual sharing schemes cannot restore to its original quality when the original input is a natural image.

The proposed scheme operates directly on the bit planes of the digital image

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2-out-of-3 Visual Cryptography

SA

SB

SC

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2-out-of-2 Visual CryptographyB

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2-out-of-2 Visual Cryptography

More reasons for the proposed schemecannot provide perfect reconstruction

intensity or spatial resolution

is not appropriate for real-time applications.

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The proposed schemeThe proposed scheme

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Example: The (2,2) proposed scheme for 4-bit imageExample: The (2,2) proposed scheme for 4-bit image

12=1011=1*23 + 0*22 + 1*21 + 15=0101=0*23 + 1*22 + 0*21 + 1

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Experiment resultsExperiment results

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ConclusionsConclusions

Preserve all the features of traditional k-out-n sharing schemesAllow for perfect reconstruction of the input B-bit imageEncrypts binary, gray-scale and color imagesCan be effectively implemented either in software or hardware