A Secure Image Encryption Algorithm Based on Rubik's Cube Principle

Table 2

Number of pixel change rate (NPCR) between images encrypted with keys 𝐾₁ and 𝐾₂ (with 1 bit difference).

Image	Mean (%)	Standard deviation (%)
Lena	99.6111	0.0251
Black	99.6064	0.0238
Baboon	99.6085	0.0253
Checkerboard	99.6113	0.0274