Weighted Polynomial-Based Secret Image Sharing Scheme with Lossless Recovery
Algorithm 1
The sharing process of the weighted polynomial-based SIS scheme.
(1)
Input: a secret image with the size of ; the threshold parameters ; participant serial numbers ; the weights ; initial share allocation list .
(2)
Output: shadow images .
(3)
Step 1. Repeat Steps 2–7 for each pixel of the secret image, where the pixel position is .
(4)
Step 2. Randomly generate any real number in the interval of [0, 1]. When , let . If has been set to 1, a random number will be generated again until the number of “1” in the share allocation list is .
(5)
Step 3. Set polynomial coefficient, where , and are assigned to a random value within the field of .
(6)
Step 4. Repeat Steps 5–6 until share values are calculated for each participant ().
(7)
Step 5. Calculate the shared value by the formula .
(8)
Step 6. If , continue or return to Step 3 and redo Steps 3–6.
(9)
Step 7. Scan the share allocation list ; if , valid values are assigned to ; if , randomly fill in the invalid value.
