NPCR and UACI measures for image encryption

Compute the NPCR and UACI measures for two encrypted images

The following code computes the Number of Pixels Change Rate (NPCR) and Unified Average Changing Intensity (UACI) measures between two encrypted versions of the same image, different only by one pixel.

So the plaintext image was first encrypted.

Then, one pixel of the plaintext was changed, and the image was encrypted again.

The NPCR and UACI measures for these two images are computed.

If the encryption is plaintext dependent, the meaasures should be the ideal ones.

Video:

https://www.youtube.com/watch?v=M16KViUjjlI

Reference:

https://link.springer.com/chapter/10.1007/978-3-030-92166-8_7