How to scramble an image?

I need to scramble an image and want to get back the orginal image. So i used the below code

im = imread('cameraman.tif');
vec = randperm(numel(im));
vec = reshape(vec, size(im));
out = im(vec);
%To reconstruct the original image
reconstruct = zeros(size(im), class(im));
reconstruct(vec) = out;

But here each time the scrambling is done randomly. Is there any method to scramble the same pixels all the time. That is how to choose the pixels to change. Please help me with this as it is an urgent need.

[Sneha P S]

Please help me with this problem

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

Answer 1

[Ameer Hamza]

Add this add beginning of your code

rng(10); % you can use any number.

this will seed random number generator with same value every time.