[Retracted] Medical Image Encryption Based on 2D Zigzag Confusion and Dynamic Diffusion

Algorithm 2

The proposed decryption algorithm.

	Input: the cipher image of size , the secret keys , , , , , , , .
	Output: the decrypted image
(1)	Stretch in a column-by-column manner.
(2)	Obtain pseudorandom sequences , , , and using equation (4) with initial values , , , .
(3)	use equation (10) with control parameters , .
	for from to 1
	use equation (11) with pseudorandom sequences , , , , and ,.
	if
	,
	else if
	,
	else
	,
	end if
	end for
(4)
	, use equation (5) with control parameters , .
	for from 1 to
	. use equation (6) with pseudorandom sequences , .
	,. use equation (7) with pseudorandom sequences and control parameters and ,.
	end for
(5)	Permute with the inverse process of 2D zigzag scan.
(6)	Decrypted image Permute with the rules of step 2 and step 3 in Section 3.1.