Table 2: Number of pixel change rate (NPCR) between images encrypted with keys 𝐾 1 and 𝐾 2 (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