DES.c

#include <stdio.h>
#include <stdlib.h>

#define ENCRYPT 0
#define DECRYPT 1

int stables[8][4][16] = 
{
  {
    {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 IP[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, 46, 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 IPInv[64] = {
    40, 8, 48, 16, 56, 24, 64, 32,
    39, 7, 47, 15, 55, 23, 63, 31,
    38, 6, 46, 14, 53, 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
};
int E[48] = {
    16, 7, 20, 21, 29, 12, 28, 17,
    1, 15, 23, 26, 5, 18, 32, 10,
    2, 8, 24, 14, 32, 27, 3, 9,
    19, 13, 30, 6, 22, 11, 4, 25
};
int P[32] = {
    16, 7, 20, 21, 29, 12, 28, 17,
    1, 15, 23, 26, 5, 18, 32, 10,
    2, 8, 24, 14, 32, 27, 3, 9,
    19, 13, 30, 6, 22, 11, 4, 25
};
int PC1[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, 57, 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 PC2[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, 35, 33, 48,
    44, 49, 39, 56, 34, 53,
    46, 42, 50, 36, 29, 32
};
int keyshifts[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };

unsigned long long roundKeys[16];

unsigned long long perm(int *permArray, unsigned long long input);
unsigned long long switchHalves(unsigned long long input);
unsigned long long DESround(unsigned long long input, int round);
void setKeySchedule(unsigned long long key);


int main(int argc, char **argv) {
    if(argc != 4)
      return -1;
    unsigned long long key = strtoull(argv[1], NULL, 10);
    unsigned long long input = strtoull(argv[2], NULL, 10);
    unsigned long long mode = strtoull(argv[3], NULL, 10);
    unsigned long long output = 0LL;
    
    setKeySchedule(key);
    for(int i = 0; i < 16; i++)
        printf("Round %i %llu\n", i, roundKeys[i]);
    if(mode == DECRYPT) {
        // Decrypt
    }
    if(mode == ENCRYPT) {
        // Encrypt
       output = perm(IP, input);
        
        for(int i=0; i<16; i++)
            output = DESround(output, i);
        
        output = switchHalves(input);
        
        output = perm(IPInv, output);
        
        printf("Encrypted: %llu\n", output);
    }
    
    return 0;
}


unsigned long long DESround(unsigned long long input, int round) {
  //  unsigned long long res;
  //  
  //  unsigned long long left = (4294967295LL << 32 & input);
 //   unsigned long long right = (4294967295LL & input);
 //   
  //  right = perm(E, right);
   
return 0LL;   
}

void setKeySchedule(unsigned long long key) {

    key = perm(PC1, key);
    unsigned long long newkey = 0LL;
    for(int i = 0; i < 16; i++) {

        newkey |= (134217727LL & key) << keyshifts[i];

        unsigned long long bit = ((1LL << 63) & key) == 0 ? 0LL : 1LL;


        newkey |= (134217727LL << 27 & key) << keyshifts[i];
        
        newkey |= (bit << 28);

        roundKeys[i] = perm(PC2, key);
    }
}

unsigned long long cyclicLeftShift(unsigned long long input, int bitsToShift) {
    return ((input) & (1LL << bitsToShift)) != 0 ? (input << 1) | 1 : (input << 1);
}

unsigned long long switchHalves(unsigned long long input) {
    
    unsigned long long res = 0LL;
    
    res |= ((4294967295LL << 32 & input) >> 32);
    res |= ((4294967295LL & input) << 32);
    
    return res;
    
}

unsigned long long perm(int *permArray, unsigned long long input) {

    int i;
    unsigned long long res = 0LL;
    int len = sizeof(permArray) / sizeof(int);
    
    
    for (i=0; i<len; i++) {

        // This is the ith bit of the output.
        unsigned long long bit = ((1LL << permArray[i]) & input) == 0 ? 0LL : 1LL;

        // Place that particular bit in location i.
        res |= (bit << i);
    }

    return res;
}