1. Matlab Image Encryption Code

(URL: http://www.cheers4all.com/2012/04/matlab-image-encryption-code/)

This project is Image Encryption & Decryption. The user will give an input and encryption factor. The image will be converted to an encrypted image file. This image is not understandable by any one. Matlab Image Encryption Code

When the receiver will receive the encrypted file he will decrypt it so he will get the original file.

We have used a simple GUI  for our cryptosystem. We have used three push buttons in our GUI representing

1. Input Image Select2. Encrypt Image3. Decrypt Image

 

Main Code:

function varargout = ImageEncryptionGui(varargin)gui_Singleton = 1;gui_State = struct('gui_Name',       mfilename, ...                   'gui_Singleton',  gui_Singleton, ...                   'gui_OpeningFcn', @ImageEncryptionGui_OpeningFcn, ...                   'gui_OutputFcn',  @ImageEncryptionGui_OutputFcn, ...                   'gui_LayoutFcn',  [] , ...                   'gui_Callback',   []);if nargin && ischar(varargin{1})    gui_State.gui_Callback = str2func(varargin{1});

end

 

if nargout    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});else    gui_mainfcn(gui_State, varargin{:});end

 

function ImageEncryptionGui_OpeningFcn(hObject, eventdata, handles, varargin)handles.output = hObject;axes(handles.axes4)%BackGr = imread('2redpanda.jpg');  %imshow(BackGr);

 

guidata(hObject, handles);clear all;clc;global Img;global EncImg;global DecImg;

 

function varargout = ImageEncryptionGui_OutputFcn(hObject, eventdata, handles)

 

varargout{1} = handles.output;function pushbutton1_Callback(hObject, eventdata, handles)

 

global Img;global key;X = uigetfile('*.jpg;*.tiff;*.ppm;*.pgm;*.png','pick a jpge file');Img = imread(X);  axes(handles.axes1)  imshow(Img);[n m k] = size(Img);  key = keyGen(n*m);guidata(hObject, handles);function pushbutton2_Callback(hObject, eventdata, handles)global Img ;global EncImg;global key;EncImg = imageProcess(Img,key);

axes(handles.axes2)imshow(EncImg);imwrite(EncImg,'Encoded.jpg','jpg');guidata(hObject, handles);

 

function pushbutton3_Callback(hObject, eventdata, handles)global DecImg;global EncImg;global key;DecImg = imageProcess(EncImg,key);axes(handles.axes3);imshow(DecImg);imwrite(DecImg,'Decoded.jpg','jpg');guidata(hObject, handles);

 

Image Process Code:

function [proImageOut] = imageProcess(ImgInp,key)[n m k] = size(ImgInp);% key =cell2mat(struct2cell( load('key5.mat')));% key = keyGen(n*m);for ind = 1 : m    Fkey(:,ind) = key((1+(ind-1)*n) : (((ind-1)*n)+n));endlen = n;bre = m;for ind = 1 : k    Img = ImgInp(:,:,ind);for ind1 = 1 : len    for ind2 = 1 : bre        proImage(ind1,ind2) = bitxor(Img(ind1,ind2),Fkey(ind1,ind2));    endendproImageOut(:,:,ind) = proImage(:,:,1);end% figure,imshow(proImageOut);return;

2. Selective Encryption Matlab Code

(URL: http://selectiveimageencryption.blogspot.in/2012/07/selective-encryption-matlab-code.html)

In an image encryption algorithm, images are protected by using encryption techniques, called fully layered; in this approach the

whole content of the images is encrypted. But in the case of selective encryption, some content of the image is unencrypted. Selective encryption algorithm reduces the execution time because it encrypts only a part of the image. Consequently, selective encryption is sometimes called partial encryption.The matlab code for selective encryption algorithm is as follows:  % Program for Selective Encryptionfunction selective_encryptiontic[i11,i12]=uigetfile('*.*');%XXXXXX Input Image XXXXXXXXXXXi12=strcat(i12,i11);im2=imread(i12);% im12=imread('1.jpg');im=imresize(im2,[400 400]);im1=im(:,:,1);

z=input('Select the key for Image Encryption  ') ;z1=z;% im1=rgb2gray(im);% im1=medfilt2(im1,[3 3]);% figure(1);subplot(2,2,1);imshow(im);title('Input Image');im2=double(im1);[M,N]=size(im2);e=hundungen(M,N,0.1);tt=0.001;

im3=mod(tt*im2+(1-tt)*e,256);a1(:,:,1)=round(im3(:,:,1));a1(:,:,2)=im(:,:,2);a1(:,:,3)=im(:,:,3);

for i=1:400    for j=1:400        a1(i,j,1)=bitxor (a1(i,j,3),a1(i,j,1));        a1(i,j,2)=bitxor (a1(i,j,1),a1(i,j,2));        a1(i,j,3)=bitxor (a1(i,j,2),a1(i,j,3));           endendfor i=1:400    for j=1:400        a1(i,j,1)=bitxor (a1(i,j,3),a1(i,j,2));        a1(i,j,2)=bitxor (a1(i,j,1),a1(i,j,3));        a1(i,j,3)=bitxor (a1(i,j,2),a1(i,j,1));           endend% for i=1:400%     for j=1:400%         a1(i,j,1)=mod((a1(i,j,3)+a1(i,j,1)),255);%         a1(i,j,2)=mod((a1(i,j,1)+a1(i,j,2)),255);%         a1(i,j,3)=mod((a1(i,j,2)+a1(i,j,3)),255);% %        %     end% end% for i=1:400%     for j=1:400%         a1(i,j,1)=mod((a1(i,j,2)+a1(i,j,3)),255);

%         a1(i,j,2)=mod((a1(i,j,3)+a1(i,j,1)),255);%         a1(i,j,3)=mod((a1(i,j,1)+a1(i,j,2)),255);% %        %     end% end% figure(2);

subplot(2,2,2);imshow(uint8(a1),[]);title('Encrypted Image');tocclc;% -----------------------------------------------------------------

if (z1==input('Enter the key '))  tice=keygen(M,N,0.1);im5=(im3-(1-tt)*e)/tt;a1(:,:,1)=round(im5(:,:,1));a1(:,:,2)=im(:,:,2);a1(:,:,3)=im(:,:,3);% for i=1:400%     for j=1:400%         a1(i,j,1)=bitxor (a1(i,j,3),a1(i,j,1));%         a1(i,j,2)=bitxor (a1(i,j,1),a1(i,j,2));%         a1(i,j,3)=bitxor (a1(i,j,2),a1(i,j,3));%        %     end% end% figure(3);

subplot(2,2,3);imshow(uint8(a1),[]);title('Final Image');figure(4);

subplot(231)imhist(uint8(im1));title('Histogram of input image');subplot(233)imhist(uint8(im3));title('Histogram of Selectively Encrypted image');subplot(234)imhist(uint8(im5));title('Histogram of final Image');elseinput('**************  Sorry,Wrong Key *******************! ');endtoc______________________________________________________function e=hundungen(M,N,key0)for(i=1:200)key0=3.925*key0*(1-key0);endkey1=3.925;for(i=1:M)    for(j=1:N)       key0=key1*key0*(1-key0);       a(i,j)=key0;    endendkey3=0.2;key2=3.925;for(i=1:M)    for(j=1:N)

        key3=key2*key3*(1-key3);        b(i,j)=key3;    endendkey4=0.3;key2=3.925;for(i=1:M)    for(j=1:N)        key4=key2*key4*(1-key4);        c(i,j)=key4;    endendt=0.4;w0=0.2;w1=0.5;w2=0.3;w=(1-t)^2*w0+2*t*(1-t)*w1+t^2*w2;for(i=1:M)   for(j=1:N)          P(i,j)=(1-t)^2*a(i,j)*w0+2*t*(1-t)*b(i,j)*w1+t^2*c(i,j)*w2;   %    d(i,j)=P(i,j)/w;   d(i,j)=P(i,j);    endendx=d;e=round(x*255);end______________________________________________________function e=keygen(M,N,key0)

for(i=1:200)key0=3.925*key0*(1-key0);endkey1=3.925;for(i=1:M)    for(j=1:N)       key0=key1*key0*(1-key0);       a(i,j)=key0;    endendkey3=0.2;key2=3.925;for(i=1:M)    for(j=1:N)        key3=key2*key3*(1-key3);        b(i,j)=key3;    endendkey4=0.3;key2=3.925;for(i=1:M)    for(j=1:N)        key4=key2*key4*(1-key4);        c(i,j)=key4;    endendt=0.4;w0=0.2;w1=0.5;w2=0.3;w=(1-t)^2*w0+2*t*(1-t)*w1+t^2*w2;

for(i=1:M)   for(j=1:N)         P(i,j)=(1-t)^2*a(i,j)*w0+2*t*(1-t)*b(i,j)*w1+t^2*c(i,j)*w2;   %    d(i,j)=P(i,j)/w;   d(i,j)=P(i,j);    endendx=d;e=round(x*255);end 

%Note:- Copy the code,selective encryption code, keygen code and hundungen function code, make seperate matlab file. Make three 'm' file in matlab.One for selective encryption, second for hundungen(M,N,key0) function and third for key generation. Save the file with file name selective _encryption. Execute the selective _encryption file and make sure both the files are in the current directory at the time of execution. Key will be numeric.________________________________________________________

Results for the given algorithm:Lena image is the input for the algorithm.

Fig.1 (a)Input Image (b)Selective Encrypted Image (c)Decrypted Image

Fig.2 (a)Histogram of the Original Image (b)Histogram of the Selectively Encrypted Image (c)Histogram of Output Image

Hence, fig.1 and fig.2 suggest that the algorithm is efficient to encrypt and decrypt the image.

Please check the following links:http://frankzhan.com/blog/2012/04/01/simple-matlab-code-encrypting-2d-image-using-hyperbolic-equation/http://www.fileguru.com/apps/matlab_codes_for_image_encryptionhttp://www.freedownloadmanager.org/download/code-image-encryption-using-matlab-4974651.html