1 //DES密码
2 /*理解算法最重要，最好自己动手实现试试看，可以使用MFC写一个简单的交互界面*/
3
4 #include<stdio.h>
5 #include<iostream>
6 #include<string.h>
7
8 #define BIT bool
9
10 using namespace std;
11
12 BIT K[16][48];
13
14 int
15 //初置换
16 IP[64] = {
17 58 , 50 , 42 , 34 , 26 , 18 , 10 , 2 ,
18 60 , 52 , 44 , 36 , 28 , 20 , 12 , 4 ,
19 62 , 54 , 46 , 38 , 30 , 22 , 14 , 6 ,
20 64 , 56 , 48 , 40 , 32 , 24 , 16 , 8 ,
21 57 , 49 , 41 , 33 , 25 , 17 , 9 , 1 ,
22 59 , 51 , 43 , 35 , 27 , 19 , 11 , 3 ,
23 61 , 53 , 45 , 37 , 29 , 21 , 13 , 5 ,
24 63 , 55 , 47 , 39 , 31 , 23 , 15 , 7},
25 //末置换
26 FP[64] = {
27 40 , 8 , 48 , 16 , 56 , 24 , 64 , 32 ,
28 39 , 7 , 47 , 15 , 55 , 23 , 63 , 31 ,
29 38 , 6 , 46 , 14 , 54 , 22 , 62 , 30 ,
30 37 , 5 , 45 , 13 , 53 , 21 , 61 , 29 ,
31 36 , 4 , 44 , 12 , 52 , 20 , 60 , 28 ,
32 35 , 3 , 43 , 11 , 51 , 19 , 59 , 27 ,
33 34 , 2 , 42 , 10 , 50 , 18 , 58 , 26 ,
34 33 , 1 , 41 , 9 , 49 , 17 , 57 , 25},
35 //密钥置换
36 KP[56] = {
37 57 , 49 , 41 , 33 , 25 , 17 , 9 , 1 ,
38 58 , 50 , 42 , 34 , 26 , 18 , 10 , 2 ,
39 59 , 51 , 43 , 35 , 27 , 19 , 11 , 3 ,
40 60 , 52 , 44 , 36 , 63 , 55 , 47 , 39 ,
41 31 , 23 , 15 , 7 , 62 , 54 , 46 , 38 ,
42 30 , 22 , 14 , 6 , 61 , 53 , 45 , 37 ,
43 29 , 21 , 13 , 5 , 28 , 20 , 12 , 4},
44 //密钥位移
45 KM[16] = {
46 1 , 1 , 2 , 2 , 2 , 2 , 2 , 2 ,
47 1 , 2 , 2 , 2 , 2 , 2 , 2 , 1},
48 //压缩置换
49 CP[48] = {
50 14 , 17 , 11 , 24 , 1 , 5 , 3 , 28 ,
51 15 , 6 , 21 , 10 , 23 , 19 , 12 , 4 ,
52 26 , 8 , 16 , 7 , 27 , 20 , 13 , 2 ,
53 41 , 52 , 31 , 37 , 47 , 55 , 30 , 40 ,
54 51 , 45 , 33 , 48 , 44 , 49 , 39 , 56 ,
55 34 , 53 , 46 , 42 , 50 , 36 , 29 , 32},
56 //扩展置换
57 EP[48] = {
58 32 , 1 , 2 , 3 , 4 , 5 , 4 , 5 ,
59 6 , 7 , 8 , 9 , 8 , 9 , 10 , 11 ,
60 12 , 13 , 12 , 13 , 14 , 15 , 16 , 17 ,
61 16 , 17 , 18 , 19 , 20 , 21 , 20 , 21 ,
62 22 , 23 , 24 , 25 , 24 , 25 , 26 , 27 ,
63 28 , 29 , 28 , 29 , 30 , 31 , 32 , 1},
64 //S盒
65 S_box[8][4][16] = {
66 //S1
67 {{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
68 {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
69 {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
70 {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}},
71 //S2
72 {{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
73 {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
74 {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
75 {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}},
76 //S3
77 {{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
78 {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
79 {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
80 {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}},
81 //S4
82 {{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
83 {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
84 {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
85 {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}},
86 //S5
87 {{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
88 {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
89 {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
90 {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}},
91 //S6
92 {{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
93 {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
94 {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
95 {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}},
96 //S7
97 {{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
98 {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
99 {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
100 {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}},
101 //S8
102 {{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
103 {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
104 {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
105 {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}}},
106 //P盒
107 PP[32] = {
108 16 , 7 , 20 , 21 , 29 , 12 , 28 , 17 ,
109 1 , 15 , 23 , 26 , 5 , 18 , 31 , 10 ,
110 2 , 8 , 24 , 14 , 32 , 27 , 3 , 9 ,
111 19 , 13 , 30 , 6 , 22 , 11 , 4 , 25};
112
113 void Initial_Permutation(BIT pt[64])
114 {
115 BIT tmp[64];
116 for(int i = 0;i < 64;i++)
117 tmp[i] = pt[IP[i]-1];
118 memcpy(pt,tmp,sizeof(tmp));
119 return ;
120 }
121
122 void Final_Permutation(BIT pt[64])
123 {
124 BIT tmp[64];
125 for(int i = 0;i < 64;i++)
126 tmp[i] = pt[FP[i]-1];
127 memcpy(pt,tmp,sizeof(tmp));
128 return ;
129 }
130
131 void P_Box_Permutation(BIT x[32])
132 {
133 BIT tmp[32];
134 for(int i = 0;i < 32;i++)
135 tmp[i] = x[PP[i]-1];
136 memcpy(x,tmp,sizeof(tmp));
137 return ;
138 }
139
140 void Generate_K(BIT SK[64])
141 {
142 BIT L[60],R[60];
143 int i,j,st;
144
145 memset(K,0,sizeof(K));
146
147 for(i = 0;i < 28;i++)
148 L[i+28] = L[i] = SK[KP[i]-1],
149 R[i+28] = R[i] = SK[KP[i+28]-1];
150 st = 0;
151 for(i = 0;i < 16;i++) {
152 st += KM[i];
153 for(j = 0;j < 48;j++)
154 K[i][j] = (CP[j] < 28)?L[CP[j] + st - 1]:R[CP[j] - 29 + st];
155 }
156 return ;
157 }
158
159 void Work(BIT L[32],BIT R[32],BIT KEY[48],int cnt)
160 {
161 BIT X[48],RES[32];
162 memset(RES,0,sizeof(RES));
163 memset(X,0,sizeof(X));
164 int i,j,a,b,st,st2,tmp;
165
166 for(i = 0;i < 48;i++)
167 X[i] = R[EP[i]-1] ^ KEY[i];
168
169 for(i = 0;i < 8;i++) {
170
171 st = i * 6;
172 a = (X[st] << 1) + X[st + 5];
173 b = (X[st + 1] << 3) + (X[st + 2] << 2) + (X[st + 3] << 1) + X[st + 4];
174 tmp = S_box[i][a][b];
175 st2 = i * 4;
176 for(j = 0;j < 4;j++)
177 RES[st2 + (3 - j)] |= (tmp >> j)&1;
178 }
179
180 P_Box_Permutation(RES);
181
182 for(i = 0;i < 32;i++)
183 L[i] ^= RES[i];
184
185 if (cnt == 15) return ;
186
187 BIT temp[32];
188
189 memcpy(temp,L,sizeof(temp));
190 memcpy(L,R,sizeof(temp));
191 memcpy(R,temp,sizeof(temp));
192
193 return ;
194 }
195
196 void DES_enc(char txt[10],char enc[10])
197 {
198 int i,j;
199 BIT L[32],R[32];
200 BIT pt[64];
201
202 for(i = 0;i < 8;i++)
203 for(j = 7;j >= 0;j--)
204 pt[i * 8 + (7 - j)] = (txt[i] >> j) & 1;
205
206 Initial_Permutation(pt);
207
208 for(i = 0;i < 32;i++)
209 L[i] = pt[i],R[i] = pt[i + 32];
210
211 for(i = 0;i < 16;i++)
212 Work(L,R,K[i],i);
213
214 for(i = 0;i < 32;i++)
215 pt[i] = L[i],pt[i + 32] = R[i];
216
217
218 Final_Permutation(pt);
219
220 for(i = 0;i < 8;i++)
221 for(j = 7;j >= 0;j--)
222 enc[i] |= pt[i * 8 + (7 - j)] << j;
223
224 return ;
225 }
226
227 void DES_dec(char txt[10],char dec[10])
228 {
229 int i,j;
230 BIT L[32],R[32];
231 BIT pt[64];
232
233 for(i = 0;i < 8;i++)
234 for(j = 7;j >= 0;j--)
235 pt[i * 8 + (7 - j)] = (txt[i] >> j) & 1;
236
237 Initial_Permutation(pt);
238
239 for(i = 0;i < 32;i++)
240 L[i] = pt[i],R[i] = pt[i + 32];
241
242 for(i = 0;i < 16;i++)
243 Work(L,R,K[15 - i],i);
244
245 for(i = 0;i < 32;i++)
246 pt[i] = L[i],pt[i + 32] = R[i];
247
248 Final_Permutation(pt);
249
250 for(i = 0;i < 8;i++)
251 for(j = 7;j >= 0;j--)
252 dec[i] |= pt[i * 8 + (7 - j)] << j;
253
254 return ;
255 }
256
257 void DES_E()
258 {
259 int tmp,i,j;
260 BIT sk[64];
261 char txt[10],key[10],res[10];
262 char Fpt[100],Fct[100];
263 FILE *P,*O;
264
265 printf("Plase enter the plaintext file:");
266 scanf("%s",Fpt);
267 printf("Plase enter the key:");
268 scanf("%s",key);
269 printf("Plase enter the ciphertext file:");
270 scanf("%s",Fct);
271
272 for(i = 0;i < 8;i++)
273 for(j = 7;j >= 0;j--)
274 sk[i * 8 + (7 - j)] = (key[i] >> j) & 1;
275
276 Generate_K(sk);
277
278 P = fopen(Fpt,"r");
279 O = fopen(Fct,"w");
280 while(tmp = fread(txt,sizeof(txt[0]),8,P)) {
281 for(i = tmp;i < 8;i++) txt[i] = 0;
282 memset(res,0,sizeof(res));
283 DES_enc(txt,res);
284 fwrite(res,sizeof(res[0]),8,O);
285 }
286 fclose(O);
287 fclose(P);
288 return ;
289 }
290
291 void DES_D()
292 {
293 int tmp,i,j;
294 BIT sk[64];
295 char txt[10],key[10],res[10];
296 char Fpt[100],Fct[100];
297 FILE *P,*O;
298
299 printf("Plase enter the ciphertext file:");
300 scanf("%s",Fpt);
301 printf("Plase enter the key:");
302 scanf("%s",key);
303 printf("Plase enter the plaintext file:");
304 scanf("%s",Fct);
305
306 for(i = 0;i < 8;i++)
307 for(j = 7;j >= 0;j--)
308 sk[i * 8 + (7 - j)] = (key[i] >> j) & 1;
309
310 Generate_K(sk);
311
312 P = fopen(Fpt,"r");
313 O = fopen(Fct,"w");
314 while (tmp = fread(txt,sizeof(txt[0]),8,P)) {
315 for(i = tmp;i < 8;i++) txt[i] = 0;
316 memset(res,0,sizeof(res));
317 DES_dec(txt,res);
318 fwrite(res,sizeof(res[0]),8,O);
319 }
320 fclose(O);
321 fclose(P);
322 return ;
323 }
324
325 int main()
326 {
327 char str[10];
328 while(1){
329 printf("选择模式---加密(E) 或 解密(D)---：");
330 scanf("%s",str);
331 if (str[0] == 'D') DES_D();
332 else if (str[0] == 'E') DES_E();
333 else return 0;
334 printf("OK...O^_^O\n");
335 }
336 }
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