VCPSS: A two-in-one two-decoding-options image sharing method combining visual cryptography (VC) and polynomial-style sharing (PSS) approaches

ESSVCS: An Enriched Secret Sharing Visual Cryptography

“…The three TiOISSS schemes [18][19][20] can be also treated as (k, k, n)-TiOISSS, which means a vague secret image is revealed by stacking any k out of n shares, and further a much finer gray-scale secret image (i.e. the covert data) is revealed by computation with these k shares.…”

“…Taking the information carrying capability into consideration, we compare the amount of covert data carried by the ESSVCS and three TiOISSSs [18][19][20].…”

“…First, the covert data carried by the ESSVCS is greater than that in Lin et al's TiOISSS [18]. Bandwidth of the proposed ESSVCS has been discussed in Theorem 4, and it can be evaluated from Table 1 and Table 2.…”

“…Bandwidth of the proposed ESSVCS has been discussed in Theorem 4, and it can be evaluated from Table 1 and Table 2. Lin et al's TiOISSS [18] groups the share matrices into different types to carry covert data according to the first row. Let m be pixel expansion of the basis matrix, where each row contains b '1' and w '0' and m=b+w.…”

“…By utilizing a (k, t, n)-ESSVCS (k ≤ t), the VC scheme that carries additional covert data where any k out of n participants can visually recover the secret by stacking the shares, any t out of n participants can restore the additional covert data by computation. There are two computer aided VCS's schemes [18,19], one is called 2-in-1 Image Secret Sharing Scheme (TiOISSS) [18,19], which is able to reveal a secret image by stacking the shares and restore a much finer gray image by computation. Li et al [20] improved Yang et al's TiOISSS [19] by gray mixing model.…”