Scrambling​+Descrambl​ing+Waterm​arking+Att​acks+Water​mark Extraction​+Decryptio​n+Problems

I am doing a project on Image watermarking using Discrete Wavelet Transform(DWT) and Encryption. It is carried out in the following steps 1.) Select the host image( Image in which watermark will be hided). 2.) Select the watermark. 3.) Encrypt the watermark using the following code as given by sir(Image analyst) 4.) Watermarking using DWT.

5.) Recover the Encrypted watermark using recovery formula.

6.) Decryption of watermark using the following code which is also attached. This is also given by Image Analyst

My Question is that I have made many attacks on Watermarked Image like Rotation, Scaling, Croping but PSNR and MSE between (Watermark and Decrypted watermark) after and before attack remain Infinity and Zero respectively.

I think During Decryption, I have used same ran permutation that I used to ENCRYPT the image. So I think, Attacks have no effect on decrypted image.

Question is how to improve my code or what suggestions you can give me.

I need Help. Though, I am trying but yr valuable suggestions can make code more effective and fast

Thanks............