how to make scrambled image?

I want to scramble a grayscale image and actually I want to have patches or square blocks and scramble by them. But before that I have to mask my image by an oval then scramble the part of image that is inside of oval, for this reason I have to make vertical and horizental strips in that oval and scramble them. Also I prefer to have ability to change size of this strips. Would you please help me by that?

I have this image:

(mary.BW)and I mask it by oval by this code:

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clear all Baselum=0; Radius=342;

X=206 Y1=78; Y2=323;

for c=1

      I=imread(['C:\Users\User\Desktop\oval mask\attached image.jpg']);
      for i=1:400
          for j=1:400
              ovaldistance=(sqrt((X-i)^2 + (Y1-j)^2)+sqrt((X-i)^2 + (Y2-j)^2));
              if ovaldistance > Radius
                  I(j,i,:)=Baselum;
              end;
          end;
      end;
      imwrite(I,['OvalMask1','attached image.jpg']);
  end;

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and the result will be like this:

(oval mask.jpg)

and now I want to scramble part of image that is in the oval. I have to make strips and flip them in order to make the image scrambled. But I don't know the right matlab function to do it. Please Help me. The result must be something like the third attached image:

Pleaaaaaasee help meeeeeeee

[Walter Roberson]

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

[Walter Roberson]

Duplicates http://www.mathworks.co.uk/matlabcentral/answers/124694-how-to-make-a-face-image-scramble-by-matlab

Answer 1

[Image Analyst]

See these:

http://www.mathworks.com/matlabcentral/fileexchange/17981-randblock

http://www.mathworks.com/matlabcentral/fileexchange/45547-jigsaw-puzzle