HideText.m

function stegoArray = HideText(carrierArray,message)
% Function HideText hides a text message in the LSB of elements within a
% 1D array (containing integers)

% Input:
%   carrierArray: A 1D array of integer values, can be row or column vector
%   and can be an array of uint8 or double values
%   message: A character vector containing a message to hide
% Output:
%   stegoArray: A 1D array of values modified to contain the hidden
%   message, same size and type as input carrierArray
%
% Author: Henry Huang

len = length(message);
stegoArray = carrierArray; %Ensure its same size and type as carrierArray

for i = 1:len
    charBits = Char2ByteArray(message(i)); % Find the character bits of letter
    for j = 1:8
        arrayI = (i-1)*8 + j; % Find array Index for this bit
        currentBit = charBits(j);
        currentValue = stegoArray(arrayI); % Find current bit and current value

        if currentBit == 1 % Check if bit is equal to 1
            if mod(currentValue,2) == 0
                stegoArray(arrayI) = currentValue + 1; % Add 1 to value if its even, leave same if odd
            end
        else % Now bit is equal to 0
            if mod(currentValue,2) == 1
                stegoArray(arrayI) = currentValue - 1;  % Subtract 1 if value is odd, leave same if even
            end
        end
    end
end
end