JSteg隐写算法, matlab代码，已实现，可运行

clc clear all;% clear all variables from previous sessions close all; covername = input('Enter image file name with extension: ', 's'); messagename = input('Enter message image file name with extension: ', 's'); cover = imread(covername); sz = size(cover); rows = sz(1,1); cols = sz(1,2); colors = max(max(cover)); %r=1; %for i=1:rows % for j=1:3:cols % rgb(r,1)=cover(i,j); % rgb(r,2)=cover(i,j+1); % rgb(r,3)=cover(i,j+2); % r=r+1; % end %end %gray=rgb2gray(rgb); %cover=gray; fd = fopen (messagename, 'r'); message = fgetl(fd); messagelength = length(message); figure(1), imshow(cover); title('Original Image (Cover Image)'); %disp(message); %cover=double(cover); %message=double(message); message = uint8(message); coverzero = cover; %disp(coverzero); %coverzero=imread('GrayScale.bmp'); quant_multiple = 1; blocksize = 8; DCT_quantizer = ... [ 16 11 10 16 24 40 51 61; ... 12 12 14 19 26 58 60 55; ... 14 13 16 24 40 57 69 56; ... 14 17 22 29 51 87 80 62; ... 18 22 37 56 68 109 103 77; ... 24 35 55 64 81 104 113 92; ... 49 64 78 87 103 121 120 101; ... 72 92 95 98 112 100 103 99 ]; %figure(1) %image(coverzero) figure(2);imshow(coverzero); %colormap(map) title('Original image'); %figure(2) %coverzero = coverzero - ceil(colors/2); %figure(2);imshow(coverzero); pad_cols = (1 - (cols/blocksize - floor(cols/blocksize))) * blocksize; if pad_cols == blocksize, pad_cols = 0; end pad_rows = (1 - (rows/blocksize - floor(rows/blocksize))) * blocksize; if pad_rows == blocksize, pad_rows = 0; end for extra_cols = 1:pad_cols coverzero(1:rows, cols+extra_cols) = coverzero(1:rows, cols); end cols = cols + pad_cols; % coverzero is now pad_cols wider for extra_rows = 1:pad_rows coverzero(rows+extra_rows, 1:cols) = coverzero(rows, 1:cols); end rows = rows + pad_rows; % coverzero is now pad_rows taller for row = 1: blocksize: rows for col = 1: blocksize: cols DCT_matrix = coverzero(row: row + blocksize-1, col: col + blocksize-1); DCT_matrix = DCT2(DCT_matrix); % quantize it (levels stored in DCT_quantizer matrix): %DCT_matrix = floor (DCT_matrix ... % ./ (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple) + 0.5); DCT_matrix = round(DCT_matrix ... ./ (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple)); %DCT_matrix=round(DCT_matrix); % place it into the compressed-image matrix: jpeg_img(row: row + blocksize-1, col: col + blocksize-1) = DCT_matrix; end end figure(3);hist(jpeg_img); figure(4);imshow(jpeg_img); bitlength=1; %messagebit=zeros(messagelength*8); for i=1:messagelength %imbed=7; for imbed=1:8 messageshift=bitshift(message(i),8-imbed); showmess=uint8(messageshift); showmess=bitshift(showmess,-7); messagebit(bitlength)=showmess; bitlength=bitlength+1; %coverindex = coverindex+1; end end %embedding i=1; for row=1:rows for col=1:cols x=jpeg_img(row,col); if (x~=0) && (x~=1) r=mod(x,2); if r==0 % if messagebit(i)==1 x=x+1; end else if messagebit(i)==0 x=x-1; end end i=i+1; end jpeg_img(row,col)=x; if i==bitlength break; end end if i==bitlength break; end end figure(5);hist(jpeg_img); % Reconstructing image recon_img = coverzero - coverzero; % zero the matrix for the reconstructed image for row = 1: blocksize: rows for col = 1: blocksize: cols IDCT_matrix = jpeg_img(row: row + blocksize-1, col: col + blocksize-1); %IDCT_matrix = floor(idct2(IDCT_matrix .* ((DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple))-0.5)); %IDCT_matrix = floor(idct2(IDCT_matrix .* (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple))); IDCT_matrix = round(idct2(IDCT_matrix .* (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple))); recon_img(row: row + blocksize-1, col: col + blocksize-1) = IDCT_matrix; end end %recon_img = recon_img + ceil(colors/2); %coverzero = coverzero + ceil(colors/2); % Clip off padded rows and columns rows = rows - pad_rows; cols = cols - pad_cols; recon_img = recon_img(1:rows, 1:cols); figure(6);imshow(recon_img); %disp(recon_img); %recon_img = recon_img - ceil(colors/2); pad_cols = (1 - (cols/blocksize - floor(cols/blocksize))) * blocksize; if pad_cols == blocksize, pad_cols = 0; end pad_rows = (1 - (rows/blocksize - floor(rows/blocksize))) * blocksize; if pad_rows == blocksize, pad_rows = 0; end for extra_cols = 1:pad_cols recon_img(1:rows, cols+extra_cols) = recon_img(1:rows, cols); end cols = cols + pad_cols; % coverzero is now pad_cols wider for extra_rows = 1:pad_rows recon_img(rows+extra_rows, 1:cols) = recon_img(rows, 1:cols); end rows = rows + pad_rows; % coverzero is now pad_rows taller jpeg_img=jpeg_img-jpeg_img; for row = 1: blocksize: rows for col = 1: blocksize: cols DCT_matrix = recon_img(row: row + blocksize-1, col: col + blocksize-1); DCT_matrix = DCT2(DCT_matrix); % quantize it (levels stored in DCT_quantizer matrix): %DCT_matrix = floor (DCT_matrix ... % ./ (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple) + 0.5); DCT_matrix = round (DCT_matrix ... ./ (DCT_quantizer(1:blocksize, 1:blocksize) * quant_multiple)); %DCT_matrix=round(DCT_matrix); % place it into the compressed-image matrix: jpeg_img(row: row + blocksize-1, col: col + blocksize-1) = DCT_matrix; %disp(jpeg_img(row: row + blocksize-1, col: col + blocksize-1)); end end stego=jpeg_img; %stego = uint8(jpeg_img); %stego = int8(jpeg_img); %disp(stego(1:8,1:8)); %stego = uint8(jpeg_img); %disp(stego(1:8,1:8)); stegoindex=1; imbed=1; messagechar=0; messageindex=1; %for i=1:(messagelength*8) for row=1:rows for col=1:cols stegomessage = stego(row,col); if (stegomessage~=0)&&(stegomessage~=1) r=mod(stegomessage,2); if (r==0) showmess=0; else showmess=1; end showmess=uint8(showmess); %showmess=bitshift(stegomessage,7); showmess=bitshift(showmess,(imbed-1)); messagechar=uint8(messagechar+showmess); stegoindex = stegoindex+1; imbed=imbed+1; if (imbed==9) messagestring(messageindex)=messagechar; messageindex=messageindex+1; messagechar=0; imbed=1; end end if (stegoindex==messagelength*8) break; end end if (stegoindex==messagelength*8) break; end end %end disp(messagestring);