//DES密碼
/*理解演算法最重要，最好自己動手實現試試看，可以使用MFC寫一個簡單的互動介面*/
#include<stdio.h>
#include<iostream>
#include<string.h>
#define BIT bool
using namespace std;
BIT K[16][48];
int
//初置換
IP[64] = {
58 , 50 , 42 , 34 , 26 , 18 , 10 , 2 ,
60 , 52 , 44 , 36 , 28 , 20 , 12 , 4 ,
62 , 54 , 46 , 38 , 30 , 22 , 14 , 6 ,
64 , 56 , 48 , 40 , 32 , 24 , 16 , 8 ,
57 , 49 , 41 , 33 , 25 , 17 , 9 , 1 ,
59 , 51 , 43 , 35 , 27 , 19 , 11 , 3 ,
61 , 53 , 45 , 37 , 29 , 21 , 13 , 5 ,
63 , 55 , 47 , 39 , 31 , 23 , 15 , 7},
//末置換
FP[64] = {
40 , 8 , 48 , 16 , 56 , 24 , 64 , 32 ,
39 , 7 , 47 , 15 , 55 , 23 , 63 , 31 ,
38 , 6 , 46 , 14 , 54 , 22 , 62 , 30 ,
37 , 5 , 45 , 13 , 53 , 21 , 61 , 29 ,
36 , 4 , 44 , 12 , 52 , 20 , 60 , 28 ,
35 , 3 , 43 , 11 , 51 , 19 , 59 , 27 ,
34 , 2 , 42 , 10 , 50 , 18 , 58 , 26 ,
33 , 1 , 41 , 9 , 49 , 17 , 57 , 25},
//金鑰置換
KP[56] = {
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},
//金鑰位移
KM[16] = {
1 , 1 , 2 , 2 , 2 , 2 , 2 , 2 ,
1 , 2 , 2 , 2 , 2 , 2 , 2 , 1},
//壓縮置換
CP[48] = {
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},
//擴充套件置換
EP[48] = {
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},
//S盒
S_box[8][4][16] = {
//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盒
PP[32] = {
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};
void Initial_Permutation(BIT pt[64])
{
BIT tmp[64];
for(int i = 0;i < 64;i++)
tmp[i] = pt[IP[i]-1];
memcpy(pt,tmp,sizeof(tmp));
return ;
}
void Final_Permutation(BIT pt[64])
{
BIT tmp[64];
for(int i = 0;i < 64;i++)
tmp[i] = pt[FP[i]-1];
memcpy(pt,tmp,sizeof(tmp));
return ;
}
void P_Box_Permutation(BIT x[32])
{
BIT tmp[32];
for(int i = 0;i < 32;i++)
tmp[i] = x[PP[i]-1];
memcpy(x,tmp,sizeof(tmp));
return ;
}
void Generate_K(BIT SK[64])
{
BIT L[60],R[60];
int i,j,st;
memset(K,0,sizeof(K));
for(i = 0;i < 28;i++)
L[i+28] = L[i] = SK[KP[i]-1],
R[i+28] = R[i] = SK[KP[i+28]-1];
st = 0;
for(i = 0;i < 16;i++) {
st += KM[i];
for(j = 0;j < 48;j++)
K[i][j] = (CP[j] < 28)?L[CP[j] + st - 1]:R[CP[j] - 29 + st];
}
return ;
}
void Work(BIT L[32],BIT R[32],BIT KEY[48],int cnt)
{
BIT X[48],RES[32];
memset(RES,0,sizeof(RES));
memset(X,0,sizeof(X));
int i,j,a,b,st,st2,tmp;
for(i = 0;i < 48;i++)
X[i] = R[EP[i]-1] ^ KEY[i];
for(i = 0;i < 8;i++) {
st = i * 6;
a = (X[st] << 1) + X[st + 5];
b = (X[st + 1] << 3) + (X[st + 2] << 2) + (X[st + 3] << 1) + X[st + 4];
tmp = S_box[i][a][b];
st2 = i * 4;
for(j = 0;j < 4;j++)
RES[st2 + (3 - j)] |= (tmp >> j)&1;
}
P_Box_Permutation(RES);
for(i = 0;i < 32;i++)
L[i] ^= RES[i];
if (cnt == 15) return ;
BIT temp[32];
memcpy(temp,L,sizeof(temp));
memcpy(L,R,sizeof(temp));
memcpy(R,temp,sizeof(temp));
return ;
}
void DES_enc(char txt[10],char enc[10])
{
int i,j;
BIT L[32],R[32];
BIT pt[64];
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
pt[i * 8 + (7 - j)] = (txt[i] >> j) & 1;
Initial_Permutation(pt);
for(i = 0;i < 32;i++)
L[i] = pt[i],R[i] = pt[i + 32];
for(i = 0;i < 16;i++)
Work(L,R,K[i],i);
for(i = 0;i < 32;i++)
pt[i] = L[i],pt[i + 32] = R[i];
Final_Permutation(pt);
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
enc[i] |= pt[i * 8 + (7 - j)] << j;
return ;
}
void DES_dec(char txt[10],char dec[10])
{
int i,j;
BIT L[32],R[32];
BIT pt[64];
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
pt[i * 8 + (7 - j)] = (txt[i] >> j) & 1;
Initial_Permutation(pt);
for(i = 0;i < 32;i++)
L[i] = pt[i],R[i] = pt[i + 32];
for(i = 0;i < 16;i++)
Work(L,R,K[15 - i],i);
for(i = 0;i < 32;i++)
pt[i] = L[i],pt[i + 32] = R[i];
Final_Permutation(pt);
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
dec[i] |= pt[i * 8 + (7 - j)] << j;
return ;
}
void DES_E()
{
int tmp,i,j;
BIT sk[64];
char txt[10],key[10],res[10];
char Fpt[100],Fct[100];
FILE *P,*O;
printf("Plase enter the plaintext file:");
scanf("%s",Fpt);
printf("Plase enter the key:");
scanf("%s",key);
printf("Plase enter the ciphertext file:");
scanf("%s",Fct);
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
sk[i * 8 + (7 - j)] = (key[i] >> j) & 1;
Generate_K(sk);
P = fopen(Fpt,"r");
O = fopen(Fct,"w");
while(tmp = fread(txt,sizeof(txt[0]),8,P)) {
for(i = tmp;i < 8;i++) txt[i] = 0;
memset(res,0,sizeof(res));
DES_enc(txt,res);
fwrite(res,sizeof(res[0]),8,O);
}
fclose(O);
fclose(P);
return ;
}
void DES_D()
{
int tmp,i,j;
BIT sk[64];
char txt[10],key[10],res[10];
char Fpt[100],Fct[100];
FILE *P,*O;
printf("Plase enter the ciphertext file:");
scanf("%s",Fpt);
printf("Plase enter the key:");
scanf("%s",key);
printf("Plase enter the plaintext file:");
scanf("%s",Fct);
for(i = 0;i < 8;i++)
for(j = 7;j >= 0;j--)
sk[i * 8 + (7 - j)] = (key[i] >> j) & 1;
Generate_K(sk);
P = fopen(Fpt,"r");
O = fopen(Fct,"w");
while (tmp = fread(txt,sizeof(txt[0]),8,P)) {
for(i = tmp;i < 8;i++) txt[i] = 0;
memset(res,0,sizeof(res));
DES_dec(txt,res);
fwrite(res,sizeof(res[0]),8,O);
}
fclose(O);
fclose(P);
return ;
}
int main()
{
char str[10];
while(1){
printf("選擇模式---加密(E) 或 解密(D)---：");
scanf("%s",str);
if (str[0] == 'D') DES_D();
else if (str[0] == 'E') DES_E();
else return 0;
printf("OK...O^_^O\n");
}
}