FPGA Implementation of Improved Security Approach for Medical Image Encryption and Decryption

Table 7

Comparative study of average correlation coefficient for Lena image.

Model	Horizontal	Vertical	Diagonal
Proposed system	−0.0003	−0.006	0.00014
Existing AES	0.2724	0.2682	0.0765
Ref. [3]	−0.0008	0.0016	0.0043
Ref. [38]	−0.000483	−0.001001	−0.001015
Ref. [34]	0.0025	0.006207	0.003041
Ref. [35]	0.004639	0.006763	0.010818
Ref. [36]	0.000101	0.00000958	0.000131
Ref [9]	0.0070	−0.0102	0.0030
Ref. [6]	−0.000400	−0.0018	0.0001
Ref. [8]	0.001	0.0017	0.0125
Ref. [39]	0.0031	—	—
Ref. [40]	0.000751	0.001133	0.001253
Ref. [12]	Proposed 1 : 0.007950	Proposed 1 : 0.007422	Proposed 1 : 0.000139
	Proposed 2 : 0.00987	Proposed 2 : 0.009145	Proposed 2 : 0.000697
	Proposed 3 : 0.007768	Proposed 3 : 0.007773	Proposed 3 : 0.000143
	Proposed 4 : 0.000914	Proposed 4 : 0.009525	Proposed 4 : 0.000711
Ref. [13]	0.01658	0.01235	0.014566
Ref. [14]	0.006150	0.006687	−0.007019
Ref. [15]	Proposed 1: −0.00093	Proposed 1: −0.001	Proposed 1: −0.00067
	Proposed 2: −0.0007	Proposed 2: −0.00059	Proposed 2: 0.00093
Ref. [41]	0.0002	−0.0133	−0.0791
Ref. [42]	−0.1242	0.0027	0.0022