I used the below code for image scrambling and unscrambling. But i didnt get the exact image in unscrambling. In the decrypted image the upper portion is at the bottom position, that is the hat in the lena image comes at bottom. Please help me to rectify it.
ite=1;
[rown,coln]=size(im);
for i=1:rown
for j=1:coln
itecount=1;
nrowp=i;
ncolp=j;
while(itecount<=ite)
newcord =[1 1;1 2]*[nrowp ncolp]';
nrowp=newcord(1);
ncolp=newcord(2);
itecount=itecount+1;
end
encim(i,j)=im((mod(nrowp,rown)+1),(mod(ncolp,coln)+1));
end
end
figure,imshow(im)
impixelinfo
figure,imshow(uint8(encim))
impixelinfo
[rown,coln]=size(encim)
for i=1:rown
for j=1:coln
itecount=1;
nrowp=i;
ncolp=j;
while(itecount<=ite)
newcord =[2 -1;-1 1]*[nrowp-1 ncolp-1]';
nrowp=newcord(1);
ncolp=newcord(2);
itecount=itecount+1;
end
decim(i,j)=encim((mod(nrowp,rown)+1),(mod(ncolp,coln)+1));
end
end
figure,imshow(uint8(decim))
impixelinfo
