Visual secret sharing scheme for k n threshold

Visual secret sharing scheme for (k, n) threshold based on QR code with multiple decryptions Source: Journal of Real-Time Image Processing (2017): 116. Authors: Wan Song, Lu Yuliang, Yan Xuehu, Wang Yongjie, Chang Chao Speaker: Huang Peng-Cheng Date: 3/4/2021 1

Outline • Introduction • Related works • Proposed scheme • Simulation results • Extensions • Conclusions • Comments 2

Introduction(1/1) --visual cryptography scheme(VCS) 3

Related works(1/2) –Wang et al. ’s scheme Wang, G. , Liu, F. , Yan, W. Q. : 2 D barcodes for visual cryptography. Multimed. Tools Appl. 75, 1– 19 (2016)

Related works(2/2) Chow, et al. ’s scheme Chow, Y. W. , Susilo, W. , Yang, G. , Phillips, J. G. , Pranata, I. , Barmawi, A. M. : Exploiting the Error Correction Mechanism in QR Codes for Secret Sharing. Springer International Publishing, New York (2016)

Proposed scheme (1/4) -- encoding process(1/1) n n {QR 1, …, QRn} Encoding procedure {SC 1, …, SCn} 6

Proposed scheme (2/4) --decoding process(1/1) SC 1 SC 2 7

Proposed scheme(3/4) -- The algorithm (1/2) (7, 7) 8

Proposed scheme(4/4) -- An example for encoding process (2, 2) VSSQR 1 1 1 1 A 2 A 3 1 A 4 QR 2 QR 1 1 1 1 QR 2 1 before 1 after 1 1

Simulation results (1/5) (2, 2) VSSQR 10

Simulation results (2/5) (2, 3) VSSQR 11

Simulation results (3/5) (2, 3) VSSQR

Simulation results (4/5) (3, 3) VSSQR 13

Simulation results (5/5) Visual quality of the revealed secret images Contrast:

Extensions

Conclusions • Meaningful shares => the decodable of QR code. • Two ways of secret revealing: • Stacking => OR operation => do not need any computational device. • XOR operation => lightweight device. 16

Comments • (k, n) or (n, n)? • (2, 100)? 17