Image Encryption Scheme Based on Block Scrambling, Closed-Loop Diffusion, and DNA Molecular Mutation

Table 2

Points substitution rule.

Operation	Base transition		Base transversion		Fixed
Random sequence	0	1	2	3	Else
A	A	G	C	A	A
T	C	T	T	G	T
G	G	A	G	T	G
C	T	C	A	C	C