Image encryption in MATLAB

which is the simplest key-less image encryption or scrambling technique?

Answer 1

[Jan]

It depends on what "simple" means. Perhaps:

• Rename it from .jpg to .avi, then opening it leads to confusing messages
• Apply a ROT13 to the bytes of the image file or image data
• A cumulative XOR looks very scrambled:

image  = rand(100, 100, 3);
stream = typecast(image, 'uint8');
for k = 2:numel(stream)
  stream(k) = xor(stream(k), stream(k - 1));
end

There are so many other simple methods, that I cannot imagine, that you won't find dozens more by your own.

[vardhit]

??? Error using ==> typecast The first input argument must be a vector.

Error in ==> Untitled3 at 2 stream = typecast(image, 'uint8');

[Jan]

As the error message implies: Make it a vector:

stream = typecast(image(:), 'uint8');