A Novel Three-Layer QR Code Based on Secret Sharing Scheme and Liner Code

Algorithm 3

Recovery algorithm of the second layer information.

	Input: Shares QR1, QR2, …, QR2^p with size of 3m × 3n.
	Output: Privacy QR code with size of m × n.
	Step 1: Construct a pixel matrix block .
	Step 2: Let i = 1, j = 1. i and j represent the rows and columns of the carrier QR code, respectively.
	Step 3: If QRk (i, j) (k = 1, 2, …, 2^p) belongs to the functional patterns of QR code, go to Step 5. Else, go to Step 4.
	Step 4: Calculate .
	Step 5: Let j = j + 3, if j < 3n, go to Step 3. Else, go to Step 6.
	Step 6: Let i = i + 3, if i < 3m, go to Step 3. Else, go to Step 7.
	Step 7: The algorithm ends.