des加密算法c++代码（des加密算法c语言实现）

本文所述实例是一个实现DES加密算法的程序代码，在C++中，DES加密是比较常用的加密算法了，且应用非常广泛。本CPP类文件可满足你的DES加密需要，代码中附带了丰富的注释，相信对于大家理解DES可以起到很大的帮助。

具体实现代码如下：

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