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 }