DES解码

 1 #ifdef  __cplusplus
 2 extern "C" {
 3 #endif
 4 
 5 void setKey(const char key[8]);
 6 char* des(const char datas[]);
 7 char * dedes(const char datas[]);
 8 
 9 #ifdef  __cplusplus
10 }
11 #endif

  1 char table_IP[]                /* 初始置换表 IP    */
  2 = {    
  3     58, 50, 42, 34, 26, 18, 10,  2,    60, 52, 44, 36, 28, 20, 12,  4,
  4     62, 54, 46, 38, 30, 22, 14,  6,    64, 56, 48, 40, 32, 24, 16,  8,
  5     57, 49, 41, 33, 25, 17,  9,  1,    59, 51, 43, 35, 27, 19, 11,  3,    
  6     61, 53, 45, 37, 29, 21, 13,  5,    63, 55, 47, 39, 31, 23, 15,  7    
  7 };
  8 
  9 const static char table_FP[]                /* 末置换表 */
 10 = {
 11     40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
 12     38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
 13     36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
 14     34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41,  9, 49, 17, 57, 25
 15 };
 16 
 17 //= {    
 18 //    40,  8, 48, 16, 56, 24, 64, 32,     39,  7, 47, 15, 55, 23, 63, 31,
 19 //    38,  6, 46, 14, 54, 22, 62, 30,        37,  5, 45, 13, 53, 21, 61, 29,
 20 //    36,  4, 44, 12, 52, 20, 60, 28,        35,  3, 43, 11, 51, 19, 59, 27,
 21 //    34,  2, 42, 10, 50, 18, 58, 26,        33,  1, 41,  9, 49, 17, 57, 25    
 22 //};
 23 
 24 char table_PC_1[]                /* 密钥置换表PC_1  */
 25 = {    
 26     57, 49, 41, 33, 25, 17,  9,     1, 58, 50, 42, 34, 26, 18,
 27     10,  2, 59, 51, 43, 35, 27,    19, 11,  3, 60, 52, 44, 36,
 28     63, 55, 47, 39, 31, 23, 15,     7, 62, 54, 46, 38, 30, 22,
 29     14,  6, 61, 53, 45, 37, 29,    21, 13,  5, 28, 20, 12,  4    
 30 };
 31 
 32 
 33 char table_PC_2[]                /* 压缩置换表 PC_2  */
 34 = {    
 35     14, 17, 11, 24,  1,  5,     3, 28, 15,  6, 21, 10,
 36     23, 19, 12,  4, 26,  8,    16,  7, 27, 20, 13,  2,
 37     41, 52, 31, 37, 47, 55,    30, 40, 51, 45, 33, 48,
 38     44, 49, 39, 56, 34, 53,    46, 42, 50, 36, 29, 32    
 39 };
 40 
 41 
 42 
 43 char table_S[8][64]              /* 48->32 bit compression tables*/
 44 = {                    /* S[1]             */
 45     14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7,
 46     0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8,
 47     4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0,
 48     15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13,
 49     /* S[2]             */
 50     15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10,
 51     3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5,
 52     0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15,
 53     13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9,
 54     /* S[3]             */
 55     10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8,
 56     13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1,
 57     13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7,
 58     1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12,
 59     /* S[4]             */
 60     7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15,
 61     13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9,
 62     10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4,
 63     3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14,
 64     /* S[5]             */
 65     2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9,
 66     14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6,
 67     4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14,
 68     11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3,
 69     /* S[6]             */
 70     12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11,
 71     10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8,
 72     9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6,
 73     4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13,
 74     /* S[7]             */
 75     4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1,
 76     13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6,
 77     1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2,
 78     6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12,
 79     /* S[8]             */
 80     13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7,
 81     1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2,
 82     7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8,
 83     2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11    
 84 };
 85 
 86 char table_P[]                /* P 盒置换  */
 87 = {    16,  7, 20, 21,    29, 12, 28, 17,     1, 15, 23, 26,     5, 18, 31, 10,
 88     2,  8, 24, 14,    32, 27,  3,  9,    19, 13, 30,  6,    22, 11,  4, 25    
 89 };
 90 
 91 char table_E[]
 92 = {
 93     32,  1,  2,  3,  4,  5,     4,  5,  6,  7,  8,  9,
 94     8,  9, 10, 11, 12, 13,    12, 13, 14, 15, 16, 17,
 95     16, 17, 18, 19, 20, 21,    20, 21, 22, 23, 24, 25,
 96     24, 25, 26, 27, 28, 29,    28, 29, 30, 31, 32,  1  
 97 };
 98 
 99 char table_move[] 
100 ={
101     1,1,2,2, 
102     2,2,2,2, 
103     1,2,2,2,
104     2,2,2,1
105 };

  1 #include<stdio.h>
  2 #include<string.h>
  3 #include"des_tables.h"
  4 #include"des.h"
  5 
  6 //保存这16轮的加密密钥<64位>
  7 char keys[17][8];
  8 //存着经过压缩置换后的 key
  9 char key_48[16][6];
 10 
 11 char data[16];
 12 //s盒置换结果缓冲区
 13 char data_32[4];
 14 char *data_left;
 15 char *data_right;
 16 
 17 
 18 //密钥置换
 19 void fun_InitReplacementKey(){
 20     register int i,j,l=0;
 21     register unsigned int k;
 22     register char *to_pos = keys[16];
 23     memset(to_pos,0,8);
 24     for(i=0,l=0;i<8;i++){
 25         for(j=7;j>0;j--){
 26             k = table_PC_1[l++]-1;                
 27             *to_pos = (*to_pos)| (( (*(keys[0]+(k>>3)) >>(7 - (k&0x07) ))&0x01  )<<j);                
 28         }
 29 
 30         to_pos++;
 31     }
 32 }
 33 
 34 //对密钥进行移位,并存在接下来下面的字节中
 35 void fun_MoveKey(int len , char*offset, char *dist){
 36     /////////////////////////
 37     ///错误了!!!! 是分两块进行循环移位 !!!!!!!
 38     ///< 已修改 ! 需要分左右部分 >
 39 
 40     register int i = len;
 41     unsigned char firstBit;
 42     static unsigned char *tmp;
 43     tmp =(unsigned char*)dist;
 44     memcpy(tmp,offset,8);
 45     firstBit =(unsigned char)tmp[0];
 46     firstBit = firstBit>>(8-len);
 47 
 48     //左边部分循环左移
 49     for(i=0;i< 3;i++){
 50         tmp[i] = (tmp[i]&0xfe) <<len ;        
 51         tmp[i] = tmp[i]|((tmp[i+1]>>(7-len))&0xff);
 52         tmp[i] = tmp[i]&0xfe;
 53     }
 54     
 55     tmp[i] = (tmp[i] &0xfe)<<len;
 56     tmp[i] = tmp[i]|(firstBit<<1);
 57     tmp[i] = tmp[i]&0xfe;
 58 
 59     firstBit =(unsigned char)tmp[++i];
 60     firstBit = firstBit>>(8-len);
 61 
 62     //右边部分循环左移
 63     for(i;i<7;i++){
 64         tmp[i] = (tmp[i]&0xfe) <<len ;        
 65         tmp[i] = tmp[i]|((tmp[i+1]>>(7-len))&0xff);
 66         tmp[i] = tmp[i]&0xfe;
 67     }
 68     tmp[i] = (tmp[i] &0xfe)<<len;
 69     tmp[i] = tmp[i]|(firstBit<<1);
 70     tmp[i] = tmp[i]&0xfe;
 71 
 72 }
 73 
 74 //对密钥进行压缩置换并保存到指定位置
 75 void fun_ReplacementCompressKey(char* offset,char *dist){
 76     //压缩置换是在 0-56位进行.需要先对64位密钥进行压缩为56位在进行48位选择
 77     register int i,j,k,l;
 78     register char dt;
 79     register unsigned char* tmp  = (unsigned char*)offset;
 80     char mid_tmp[7];
 81 
 82     for(i=0;i<7;i++){
 83         mid_tmp[i] = (tmp[i]<<(i)) | ((tmp[i+1])>>(7-i));
 84     }        
 85 
 86     memset(dist,0,7);
 87     //进行置换
 88     for(i=0,l=0;i<6;i++){
 89         for(dt =0,j=7;j>=0;j--){
 90             k = table_PC_2[l++]-1;        
 91             dt = dt|(( (*(mid_tmp+(k>>3)) >>(7 - k&0x07 ))&0x01  )<<j);
 92             if(j==0)
 93                 break;
 94         }
 95         dist[i] = dt;
 96     }
 97 }
 98 
 99 /**********************************************/
100 
101 
102 /**********************************************/
103 //加密过程
104 
105 //初始置换 ip 
106 //从offset位置开始将数据置换到 data[8-15]字节 ,然后重新复制到data[0-7]中
107 void fun_initReplacement(const char *offset){
108     register int i,j,l;
109     register unsigned char k,*tmp,*to;
110     //将数据块区域重置为 0 
111     tmp = (unsigned char*)offset;
112     to = (unsigned char* )(data+8);
113     memset(to,0,8);
114     for(i=0,l=0;i<8;i++){
115         for(j=7;j>=0;j--){
116             k = table_IP[l++]-1;
117             to[i] = to[i] | ((( *(tmp+(k>>3))>>(7- (k &0x07)))&0x01)<<j);
118             if(j==0)
119                 break;
120         }
121     }
122     memcpy(data,data+8,8);
123     //初始化指针
124     data_left = data;
125     data_right = data+4;
126 }
127 
128 //末置换 fp
129 void fun_finalReplacement(){
130     //数据块存在 data[0]-data[7]中 !
131     //置换临时空间 data[8]-data[15]    
132     register int i,j,l;
133     register unsigned char k,*tmp,*to;
134     //将数据块区域重置为 0 
135     tmp = (unsigned char*)data;
136     to = (unsigned char*)(data+8);
137     for(i=0,l=0;i<8;i++){
138         for(j=7;j>=0;j--){
139             k = table_FP[l++]-1;
140             to[i] = to[i] | ((( *(tmp+(k>>3))>>(7- (k &0x07)))&0x01)<<j);
141             if(j==0)
142                 break;
143         }
144     }
145     memcpy(data,to,8);
146 
147 }
148 
149 //扩展置换
150 void fun_expandReplacement_32To48(){
151     //////////将右边的数据扩展至 48 位 !
152     register int i,j;
153     register unsigned char k,l,*tmp,*to_pos;
154     tmp = (unsigned char *)data_right;
155     to_pos = (unsigned char*)(data+8);
156     memset(to_pos,0,8);
157     //printf("\n---------- 扩展置换 ---------\n");
158     for(i=0,l=0;i<6;i++){
159         for(j=7 ,k=0;j>=0;j--){
160             k = table_E[l++]-1;
161             *to_pos = (*to_pos)| (((*(tmp+(k>>3)) >>(7 - (k&0x07) ))&0x01)<<j);
162             //printf("%d  %d  %x \n",l,k,((*(tmp+(k>>3)) >>(7 - (k&0x07) ))&0x01));
163             if(j==0)
164                 break;
165         }
166         to_pos++;
167     }
168 }
169 
170 //加 密钥 异或
171 void fun_xor_48(char *ktmp){
172     register int i;
173     char *dtmp = data+8;
174     for(i=0;i<6;i++){
175         dtmp[i] = dtmp[i]^ktmp[i];
176 
177     }
178 }
179 
180 // s盒置换
181 void fun_S_Replacement(){
182     // s盒工作原理 : 48位 分成8组.每组6位   0位和5位组成行定位, 1-4位组成列定位.
183     // 定位出来的数据即为替换后的 4 位数据
184     register unsigned char row,col,ctmp,index,i;
185     register char *dtmp;
186     static char tmp[4];
187     dtmp = data+8;
188     memset(tmp,0,4);
189     //((*(tmp+(k>>3)) >>(7 - (k&0x07) ))&0x01)
190     for(index =0,ctmp=0,i=0;i< 8 ;i++){
191         // row 为:index 接下来第零位和第五位
192         row = (((*(dtmp+((index)>>3))>>((7-((index)&0x07))))&0x01)<<1); //第0位
193         row|=(((*(dtmp+((index+5)>>3))>>((7-((index+5)&0x07))))&0x01))&0x03;//第5位
194 
195         col =(((*(dtmp+((index+1)>>3))>>((7-((index+1)&0x07))))&0x01)<<3); //第1位
196             col|= (((*(dtmp+((index+2)>>3))>>((7-((index+2)&0x07))))&0x01)<<2);    //第2位
197             col|= (((*(dtmp+((index+3)>>3))>>((7-((index+3)&0x07))))&0x01)<<1);    //第3位
198             col|= (((*(dtmp+((index+4)>>3))>>((7-((index+4)&0x07))))&0x01))&0x0f;//第4位
199         ctmp = table_S[i][(row<<4)+col];
200 
201         //写入4位
202         tmp[i>>1] = tmp[i>>1] | ((ctmp&0xf)<<(((~i)&0x01)<<2));
203         index+=6;
204     }
205     memcpy(data+8,tmp,4);
206 }
207     
208 
209 //P盒置换
210 void fun_P_Replacement(){
211     register unsigned char i,k,l;
212     static char tmp[4],j;
213     register char *offset =data + 8;
214     memset(tmp,0,4);
215     for(i=0,l=0;i<4;i++){
216         for(k=0,j=7;j>=0;j--){
217             k = table_P[l++]-1;            
218             tmp[i] = tmp[i] |((( * (offset+(k>>3)))>>(7 - (k&0x07))&0x01)<<j);
219             if(j==0)
220                 break;
221         }
222     }    
223     memcpy(data+8,tmp,4);
224 }
225 
226 //左右域异或
227 void fun_xor_32(){
228     register char i;
229     for(i=0;i<4;i++){
230         data_left[i] = data_left[i]^data[8+i];
231     }
232 }
233 
234 
235 //设置 密码 <生成过程所有密码>
236 void setKey(const char key[8]){    
237     register int i;
238     register char*offset,*to,*ct;
239     memcpy(keys[0],key,8);
240     fun_InitReplacementKey();
241     offset =  keys[16];
242     to = keys[0];
243     ct = key_48[0];
244     //16轮迭代算出需要的 <key>
245     for(i=0;i<16;i++){
246         fun_MoveKey(table_move[i],offset,to);
247         fun_ReplacementCompressKey(to,ct);
248         offset = to;
249         ct+=6;
250         to+=8;
251     }
252 }
253 
254 
255 //加密
256 char* des(const char datas[]){
257     int i=0;
258     static char *swapeTmp;
259     fun_initReplacement(datas);
260     for(i=0;i<15;i++){
261         fun_expandReplacement_32To48();
262         fun_xor_48(key_48[i]);
263         fun_S_Replacement();
264         fun_P_Replacement();
265         fun_xor_32();
266         swapeTmp = data_left;        
267         data_left =data_right;
268         data_right =swapeTmp;
269     }//经检验前 15 轮可以正确运算...
270     {//第16轮
271         fun_expandReplacement_32To48();
272         fun_xor_48(key_48[i]);
273         fun_S_Replacement();
274         fun_P_Replacement();
275         fun_xor_32();
276         //printf("\n---- 16 轮-----\nData: %x Left: %x Right: %x ",data,data_left,data_right);
277         //现在状况是 data<right,left>需要将 left 和right的数据块调换过来!!!!!!
278         memcpy(data+8,data,4);
279         memcpy(data,data+4,4);
280         memcpy(data+4,data+8,4);
281         memset(data+8,0,8);
282     }
283     //末置换!
284     fun_finalReplacement();
285     return data;
286 }
287 
288 //解密算法
289 char * dedes(const char datas[]){
290     int i=0;
291     static char *swapeTmp;
292     fun_initReplacement(datas);
293     for(i=15;i>0;i--){
294         fun_expandReplacement_32To48();
295         fun_xor_48(key_48[i]);
296         fun_S_Replacement();
297         fun_P_Replacement();
298         fun_xor_32();
299         swapeTmp = data_left;        
300         data_left =data_right;
301         data_right =swapeTmp;
302     }//经检验前 15 轮可以正确运算...
303     {//第16轮
304         fun_expandReplacement_32To48();
305         fun_xor_48(key_48[i]);
306         fun_S_Replacement();
307         fun_P_Replacement();
308         fun_xor_32();
309         //现在状况是 data<right,left>需要将 left 和right的数据块调换过来!!!!!!
310         memcpy(data+8,data,4);
311         memcpy(data,data+4,4);
312         memcpy(data+4,data+8,4);
313         memset(data+8,0,8);
314     }
315     //末置换!
316     fun_finalReplacement();
317     data[8]=‘\0‘;
318     return data;
319 }