des.cpp

DES加密解密算法的C++实现

#include <stdio.h>

int IP[]={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};
int PC1[]={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};
int LS[]={ 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
int RS[]={ 0, 1, 2, 2, 2, 2, 2 ,2, 1, 2, 2, 2, 2, 2, 2, 1};
int PC2[]={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};
int EE[]={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};
int SS[][64]={{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},
              {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},
              {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},
              {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},
              {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},
              {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},
              {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},
              {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}};
int PP[]={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};
int IN[]={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};

void DES(int source[],int key[],int dest[],int flag) {
    int i,j,k,t1,t2;
    int ns[64],nk[64],ts[64],tk[64];
    for(i=0;i<64;i++)   ns[i]=source[IP[i]-1];              // IP
    for(i=0;i<56;i++)   nk[i]=key[PC1[i]-1];                // PC1
    for(i=0;i<16;i++) {
        for(j=0;(flag)&&(j<LS[i]);j++) {                    // LS
            t1=nk[0],t2=nk[28];
            for(k=1;k<28;k++)   nk[k-1]=nk[k],nk[k-1+28]=nk[k+28];
            nk[28-1]=t1,nk[56-1]=t2;
        }
        for(j=0;(!flag)&&(j<RS[i]);j++) {                   // RS
            t1=nk[28-1],t2=nk[56-1];
            for(k=28-1;k>=1;k--)  nk[k]=nk[k-1],nk[k+28]=nk[k-1+28];
            nk[0]=t1,nk[28]=t2;
        }
        for(j=0;j<48;j++)   tk[j]=nk[PC2[j]-1];             // PC2
        for(j=0;j<32;j++)   dest[j]=ns[j+32];
        for(j=0;j<48;j++)   ts[j]=ns[EE[j]-1+32];           // EE
        for(j=0;j<48;j++)   ts[j]=ts[j]^tk[j];              // XOR
        for(j=0;j<8;j++) {                                  // SS
            t1=(ts[j*6]<<1)|(ts[j*6+5]);
            t2=(ts[j*6+1]<<3)|(ts[j*6+2]<<2)|(ts[j*6+3]<<1)|(ts[j*6+4]);
            for(k=3;k>=0;k--)
                ns[j*4+k+32]=(SS[j][t1*16+t2]>>k)&1;
        }
        for(j=0;j<32;j++)   dest[j+32]=ns[PP[j]-1+32];      // PP
        for(j=0;j<32;j++)   dest[j+32]=dest[j+32]^ns[j];    // XOR
        for(j=0;j<64;j++)   ns[j]=dest[j];
    }
    for(i=0;i<32;i++)                                       // SWAP(L,R)
        j=ns[i],ns[i]=ns[i+32],ns[i+32]=j;
    for(i=0;i<64;i++)   dest[i]=ns[IN[i]-1];                // IP-1
}

int main()
{
    return 0;
}