Analytic Study of a Novel Color Image Encryption Method Based on the Chaos System and Color Codes

Table 4

Estimate of critical values of NPCR and UACI.

Image encryption algorithm	Obtained value	NPCR test results
		0.05 level	0.01 level	0.001 level
		Theoretical NPCR values
		99.5693%	99.5527%	99.5341%
Proposed algorithm	99.61%	Pass	Pass	Pass
		UACI test results
		0.05 level	0.01 level	0.001 level
		Theoretical UACI values
		33.2824–33.6447%	33.2255–33.7016%	33.1594–33.7677%
Proposed algorithm	33.46%	Pass	Pass	Pass