Can rc4 encryption applied for color images?

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Anushka 2015-8-4

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https://ww2.mathworks.cn/matlabcentral/answers/232275-can-rc4-encryption-applied-for-color-images

关闭： Walter Roberson 2018-7-23

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The following code for rc4 encryption and decryption for grayscale images.Can this be also used for color images?

function EI = endecryptImage(I, key)
keylength = length(key);
[m p] = size(I);
S = 0:255;
j = 1;
for i = 1:256
      j = 1 + mod(j + S(i) + key(1 + mod(i, keylength)), 256);
      tmp = S(i);
      S(i) = S(j);
      S(j) = tmp; %swap(S(i), S(j))
  end
  i = 1;
  j = 1;
  n = numel(I);
   EI = zeros(1, n); % or EI = zeros(m, p), this enable us to avoid reshaping result
  for k = 1:n
      i = 1 + mod(i + 1, 256);
      j = 1 + mod(j + S(i), 256);
      tmp = S(i);
      S(i) = S(j);
      S(j) = tmp; %swap(S(i), S(j))
      Ks = 1 + mod(S(i) + S(j), 256);
      EI(k) = bitxor(S(Ks), I(k));
  end
  EI = reshape(EI, m, p);