desordtext.m

steganography tools to hide a text file in an image in true colour.

function desordtext(F,y)
%------------------------------------------------------------------------------------------
%  DESORDTEXT
%
%  The following program disorders a text file transforming it into a matrix.    
% 
%  and disordering for lines and columns and then he it transform it into a vector.
%
%  Author: Francisco Echegorri  
%  E-mail: [e-mail]  
%  Created in September of 2002. 
%------------------------------------------------------------------------------------------
%  El siguiente programa desordena un archivo de texto convirtiendolo en una matrix
%  y desordenando por filas y columnas para luego convertirlo en un vector.
%------------------------------------------------------------------------------------------

if nargin==0
   x=input('Enter a password (of up to 24 letters)\n','s');
   [y, pathname] = uigetfile('*.*', 'Select the Text File ');
   buffer=pwd;
   cd (pathname);
   cd (buffer);fid=fopen(y,'rt');F=fread(fid);F=char(F)';
  else x=input('Enter a password (of up to 24 letters)\n','s');
end
clc,n=length(F);
x=dalfa(x);x=keyexpansion(x);
m=fix(sqrt(n)); %It calculates the side of the matrix.
for i=1:m
   X(i,1:m)=F(1:m);lon=length(F);F=F(m+1:lon);%It orders the numbers in a square matrix.
end
p=m+1;long=length(F);
while long>=m
   X(p,1:m)=F(1:m);lon=length(F);F=F(m+1:lon);p=p+1;long=length(F);
end
X(p,1:long)=F(1:long);X(p,long+1:m)=255;%Those that they lack are completed with 255.
MC=size(X(1,:));MF=size(X(:,1));NC=MC(1,2);NF=MF(1,1);w=x.*997;x=w-fix(w);
y=randpermut(x,NF);z=randpermut(x,NC);
for i=1:NF
   Y(i,:)=X(y(i),:);%It disorders for lines.
end
for j=1:NC
   Z(:,j)=Y(:,z(j));%It disorders for columns.
end
F=[];
for i=1:NF
   a=Z(i,1:NC);F=[F,a]; %It transforms it into a vector.
end
save htext F   %He stays in format mat in htext.
load htext,u=char(F);
disp('                                 ')
disp('The crypt text is in htext:')
disp('                                     ')
disp(u)