www.pudn.com > 11DES_encryption.rar > DES.m
% function C=DES(M,K)
%% ---------------------------------------------------------------
% 数据加密标准DES算法的Matlab实现
% 输入明文M和密钥K用16进制数表示，字符串格式
%--------------------------------------------------------------------------
%% ---------------第一步：数据初始化--------------------------------
%以字符串形式输入的明文和密钥转换成01数字串
%明文和密钥
clear
clc
% M为16进制初始值，即64位明文组
M = 'AF33333333555325';
% K为64为密文组
K = '1111111111111111';
% 分配存储空间
MB=[];
for i=1:16
Mi=M(i);
MBi=['0000',dec2bin(hex2dec(Mi))];
MBi=MBi(end-3:end);
MBi=[str2num(MBi(1)),str2num(MBi(2)),str2num(MBi(3)),str2num(MBi(4))];
% MBi = [dec2bin(hex2dec(Mi))];
% MBi = [str2num(MBi)];
MB=[MB,MBi];
end
M=MB;
KB=[];
for i=1:16
Ki=K(i);
KBi=['0000',dec2bin(hex2dec(Ki))];
KBi=KBi(end-3:end);
KBi=[str2num(KBi(1)),str2num(KBi(2)),str2num(KBi(3)),str2num(KBi(4))];
KB=[KB,KBi];
end
K=KB;
% E-盒扩展置换；E = 6*8 =48.
E=[32, 1, 2, 3, 4, 5;
4, 5, 6, 7, 8, 9;
8, 9,10,11,12,13;
12,13,14,15,16,17;
16,17,18,19,20,21;
20,21,22,23,24,25;
24,25,26,27,28,29;
28,29,30,31,32,1];
% 8个S-盒查表；Sx = 4*16 = 64
S1=[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7;
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8;
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0;
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13];
S2=[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10;
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5;
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15;
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9];
S3=[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8;
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1;
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7;
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12];
S4=[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15;
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9;
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4;
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14];
S5=[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9;
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6;
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14;
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3];
S6=[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11;
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8;
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6;
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13];
S7=[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1;
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6;
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2;
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12];
S8=[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7;
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2;
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8;
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11];
% P = 1*32
P=[16,7,20,21,29,12,28,17,1,15,23,26,5,18,31,10,2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25];
% PC1 = 1*56
PC1=[57,49,41,33,25,17,9,1,58,50,42,34,26,18,10,2,59,51,43,35,27,19,11,3,60,52,44,36,63,55,47,39,31,23,15,7,62,54,46,38,30,22,14,6,61,53,45,37,29,21,13,5,28,20,12,4];
% PC2 = 1*48
PC2=[14,17,11,24,1,5,3,28,15,6,21,10,23,19,12,4,26,8,16,7,27,20,13,2,41,52,31,37,47,55,30,40,51,45,33,48,44,49,39,56,34,53,46,42,50,36,29,32];
%% -----------------第二步：产生子密钥------------------------------
% Ki初始空间分配
Ki=zeros(16,48);
% 压缩变换PC-1
K_PC1=K(PC1); %经过密钥初始置换
% 分割得到C0,D0
C0=K_PC1(1:28);
D0=K_PC1(29:56);
% 移位的实现
for i=1:16
if i==1||i==2||i==9||i==16 %第1、2、9、16轮循环左移1位
C0=[C0(2:end),C0(1)];
D0=[D0(2:end),D0(1)];
else %其它轮循环左移2位
C0=[C0(3:end),C0(1:2)];
D0=[D0(3:end),D0(1:2)];
end
% 合并
K_LS=[C0,D0];
% 压缩变换PC-2,i--->1 to 16,实现16轮迭代运算
Ki(i,:)=K_LS(PC2);
end
%% -----------------第三步：16轮循环加密----------------------------
% 没有做初始换位和逆初始换位处理
L=M(1:32); %输入的左半部分明文
R=M(33:64);%输入的右半部分明文
%以下是16轮迭代
for i=1:16
E0=reshape(E',1,48); %把E盒转换成行向量
R_E=R(E0); %E盒扩展
R_Ki=mod(R_E+Ki(i,:),2);%与子密钥相加
%经过S1盒;
% 每个S-盒有6位输入，4位输出。
B=R_Ki(1:6);
% 2进制转换为10进制，加1是因为矢量索引从1开始。
x=B(1)*2+B(6)+1; % x-->b1b6
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1; % y-->b2b3b4b5
C=['0000',dec2bin(S1(x,y))]; % 字符串处理
C=C(end-3:end);
C1=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S2盒
B=R_Ki(7:12);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S2(x,y))];
C=C(end-3:end);
C2=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S3盒
B=R_Ki(13:18);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S3(x,y))];
C=C(end-3:end);
C3=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S4盒
B=R_Ki(19:24);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S4(x,y))];
C=C(end-3:end);
C4=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S5盒
B=R_Ki(25:30);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S5(x,y))];
C=C(end-3:end);
C5=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S6盒
B=R_Ki(31:36);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S6(x,y))];
C=C(end-3:end);
C6=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S7盒
B=R_Ki(37:42);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S7(x,y))];
C=C(end-3:end);
C7=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
%经过S8盒
B=R_Ki(43:48);
x=B(1)*2+B(6)+1;
y=B(2)*8+B(3)*4+B(4)*2+B(5)+1;
C=['0000',dec2bin(S8(x,y))];
C=C(end-3:end);
C8=[str2num(C(1)),str2num(C(2)),str2num(C(3)),str2num(C(4))];
C=[C1,C2,C3,C4,C5,C6,C7,C8];%经过8个S盒的结果合并起来
%经过P盒置换
R_P=C(P);
%交换左右两半部分
TEMP=L;
L=R;
R=mod(TEMP+R_P,2); % mod(x,2)即将x变换为2进制序列。
end
%交换左右两半部分
TEMP=L;
L=R;
R=TEMP;
%输出密文
C=[L,R];
CS=[];
C=num2str(C);
pos=find(C~=' ');
C=C(pos);
for i=1:4:61
Ci=C(i:i+3);
CS=[CS,num2str(dec2hex(bin2dec(Ci)))];
end
C=CS