Index error in code

I am trying to execute this code but it gives me an error Index exceeds array bounds.

  I= [234, 112, 22, 56; 78, 81, 119, 121; 98 193 250 211; 33 135 199 201];
  s=[110 45 32; 95 150 67; 89 76 55];
  s2= s(I+1)

[KSSV]

What you are doing is wrong. You are trying to access more number of elements from s. What exactly you want to do?

[Abdullah Qayyum]

I am applying sbox on an encrypted image.

Answer 1

[Dhruv]

Hi @Abdullah Qayyum

The error is being encountered because you're using values from matrix I to index into matrix s, which only has 9 elements (3x3 matrix). MATLAB uses 1-based indexing, so the valid index range for s is 1 to 9. However, elements in I+1 go well beyond this range (up to 251), causing the "Index exceeds the number of array elements" error.

To fix it, either make s a vector with at least max(I(:)) + 1 elements or ensure the values in I+1 do not exceed 9.

I hope this helps!