*4.5. Resistance Against Chosen-plain Text Attack*

To resist chosen-plain text attacks, an encryption system must have strong plaintext sensitivity. Similarly, plaintext sensitivity can use the same key to encrypt two distinct plaintext images, and calculate the NPCR and UACI values of the two images. We calculated the average NPCR and UACI for obtaining two cipher images 200 times, by performing two rounds of encryption in Table 3 .


**Table 3.** The NPCR and UACI of chosen-plain text analysis.
