• DES算法实现(C++版)


      1 #include "memory.h"
      2 #include "stdio.h"
      3 enum {encrypt,decrypt};//ENCRYPT:加密,DECRYPT:解密
      4 void des_run(char out[8],char in[8],bool type=encrypt);
      5 //设置密钥
      6 void des_setkey(const char key[8]);
      7 static void f_func(bool in[32],const bool ki[48]);//f函数
      8 static void s_func(bool out[32],const bool in[48]);//s盒代替
      9 //变换
     10 static void transform(bool *out, bool *in, const char *table, int len);
     11 static void xor(bool *ina, const bool *inb, int len);//异或
     12 static void rotatel(bool *in, int len, int loop);//循环左移
     13 //字节组转换成位组
     14 static void bytetobit(bool *out,const char *in, int bits);
     15 //位组转换成字节组
     16 static void bittobyte(char *out, const bool *in, int bits);
     17 //置换IP表
     18 const static char ip_table[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};
     19 //逆置换IP-1表
     20 const static char ipr_table[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};
     21 //E 位选择表
     22 static const char e_table[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};
     23 //P换位表
     24 const static char p_table[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};
     25 //pc1选位表
     26 const static char pc1_table[56]={
     27 57,49,41,33,25,17,9,1,
     28 58,50,42,34,26,18,10,2,
     29  59,51,43,35,27,19,11,3,
     30 60,52,44,36,63,55,47,39,
     31 31,23,15,7,62,54,46,38,
     32  30,22,14,6,61,53,45,37,
     33 29,21,13,5,28,20,12,4
     34 };
     35 //pc2选位表
     36 const static char pc2_table[48]={
     37   14,17,11,24,1,5,3,28,
     38  15,6,21,10,23,19,12,4,
     39 26,8,16,7,27,20,13,2,
     40 41,52,31,37,47,55,30,40,
     41  51,45,33,48,44,49,39,56,
     42  34,53,46,42,50,36,29,32
     43 };
     44 //左移位数表
     45 const static char loop_table[16]={1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
     46 //S盒
     47 const static char s_box[8][4][16]={
     48  //s1
     49  14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
     50  0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
     51  4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
     52  15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13,
     53  //s2
     54  15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
     55  3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
     56  0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
     57  13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9,
     58  //s3
     59  10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
     60  13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
     61  13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
     62  1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12,
     63  //s4
     64  7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
     65  13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
     66  10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
     67  3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14,
     68  //s5
     69  2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
     70  14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
     71  4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
     72  11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3,
     73  //s6
     74  12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
     75  10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
     76  9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
     77  4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13,
     78  //s7
     79  4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
     80  13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
     81  1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
     82  6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12,
     83  //s8
     84  13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
     85  1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
     86  7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
     87  2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
     88 };
     89 static bool subkey[16][48];//16圈子密钥
     90 void des_run(char out[8],char in[8], bool type)
     91 {
     92  static bool m[64],tmp[32],*li=&m[0], *ri=&m[32];
     93  bytetobit(m,in,64);
     94  transform(m,m,ip_table,64);
     95  if(type==encrypt){
     96  for(int i=0;i<16;i++){
     97  memcpy(tmp,ri,32);
     98  f_func(ri,subkey[i]);
     99  xor(ri,li,32);
    100  memcpy(li,tmp,32);
    101  }
    102  }else{
    103  for(int i=15;i>=0;i--){
    104  memcpy(tmp,li,32);
    105  f_func(li,subkey[i]);
    106  xor(li,ri,32);
    107  memcpy(ri,tmp,32);
    108  }
    109  }
    110  transform(m,m,ipr_table,64);
    111  bittobyte(out,m,64);
    112 }
    113 void des_setkey(const char key[8])
    114 {
    115  static bool k[64], *kl=&k[0], *kr=&k[28];
    116  bytetobit(k,key,64);
    117  transform(k,k,pc1_table,56);
    118  for(int i=0;i<16;i++)
    119  {
    120  rotatel(kl,28,loop_table[i]);
    121  rotatel(kr,28,loop_table[i]);
    122  transform(subkey[i],k,pc2_table,48);
    123  }
    124 }
    125 void f_func(bool in[32],const bool ki[48])
    126 {
    127  static bool mr[48];
    128  transform(mr,in,e_table,48);
    129  xor(mr,ki,48);
    130  s_func(in,mr);
    131  transform(in,in,p_table,32);
    132 }
    133 void s_func(bool out[32],const bool in[48])
    134 {
    135  for(char i=0,j,k;i<8;i++,in+=6,out+=4)
    136  {
    137  j=(in[0]<<1)+in[5];
    138  k=(in[1]<<3)+(in[2]<<2)+(in[3]<<1)+in[4];
    139  bytetobit(out,&s_box[i][j][k],4);
    140  }
    141 }
    142 void transform(bool *out,bool *in,const char *table,int len)
    143 {
    144  static bool tmp[256];
    145  for(int i=0;i<len;i++)
    146  tmp[i]=in[table[i]-1];
    147  memcpy(out,tmp,len);
    148 }
    149 void xor(bool *ina,const bool *inb,int len)
    150 {
    151  for(int i=0;i<len;i++)
    152  ina[i]^=inb[i];
    153 }
    154 void rotatel(bool *in,int len,int loop)
    155 {
    156  static bool tmp[256];
    157  memcpy(tmp,in,loop);
    158  memcpy(in,in+loop,len-loop);
    159  memcpy(in+len-loop,tmp,loop);
    160 }
    161 void bytetobit(bool *out,const char *in,int bits)
    162 {
    163  for(int i=0;i<bits;i++)
    164  out[i]=(in[i/8]>>(i%8)) &1;
    165 }
    166 void bittobyte(char *out,const bool *in,int bits)
    167 {
    168  memset(out,0,(bits+7)/8);
    169  for(int i=0;i<bits;i++)
    170  out[i/8]|=in[i]<<(i%8);
    171 }
    172 void main()
    173 {
    174  char key[8]={'p','r','o','g','r','a','m'},str[8];
    175  puts("*****************DES***********************");
    176  printf("
    ");
    177  printf("
    ");
    178  puts("please input your words");
    179  gets(str);
    180  printf("
    ");
    181  puts("****************************************");
    182  des_setkey(key);
    183  des_run(str,str,encrypt);
    184  puts("after encrypting:");
    185  puts(str);
    186  printf("
    ");
    187  puts("****************************************");
    188  puts("after decrypting:");
    189  des_run(str,str,decrypt);
    190  puts(str);
    191  printf("
    ");
    192  puts("****************************************");
    193  printf("
    ");
    194 }
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  • 原文地址:https://www.cnblogs.com/jiu0821/p/9172472.html
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