//Slide Attack
//theamazingking.com

#include <stdio.h>

unsigned int sbox[16] = {2, 6, 1, 13, 0, 5, 8, 7, 14, 10, 15, 11, 4, 9, 3, 12};

unsigned int revSbox[16] = {4, 2, 0, 14, 12, 5, 1, 7, 6, 13, 9, 11, 15, 3, 8, 10};

unsigned int realK0, realK1;

unsigned int plain[200];
unsigned int cipher[200];

unsigned int fullSbox(unsigned int a)
{
    unsigned int left = (a >> 4) & 0xf;
    unsigned int right = a & 0xf;

    left = sbox[left];
    right = sbox[right];

    return left << 4 | right;
}

unsigned int fullRevSbox(unsigned int a)
{
    unsigned int left = (a >> 4) & 0xf;
    unsigned int right = a & 0xf;

    left = revSbox[left];
    right = revSbox[right];

    return left << 4 | right;
}

unsigned int oneRound(unsigned int a, unsigned int k)
{
    return fullSbox(a ^ k);
}

unsigned int encrypt(unsigned int plain, unsigned int k0, unsigned int k1)
{
    int c;
    for(c = 0; c < 100; c++)
    {
        if ((c % 2) == 0)   //EVEN ROUNDS
            plain = oneRound(plain, k0);
        else
            plain = oneRound(plain, k1);
    }

    return plain;
}

unsigned int slidePair(unsigned int plain1, unsigned int cipher1, unsigned int plain2, unsigned int cipher2)
{
    int k0;
    for(k0 = 0; k0 <= 0xff; k0++)
    {
        unsigned int k1 = fullSbox(cipher1 ^ k0) ^ fullRevSbox(cipher2);

        unsigned int testPlain2 = fullSbox(fullSbox(plain1 ^ k0) ^ k1);

        if (testPlain2 == plain2)
        {
                //VERIFY
                int crapped = 0;
                int c;
                for(c = 0; c < 10; c++)
                {
                    if (encrypt(plain[c], k0, k1) != cipher[c])
                    {
                        crapped = 1;
                        break;
                    }
                }
                if (crapped) continue;
               // printf("REAL    K0 = %x  K1 = %x\n", realK0, realK1);
               // printf("  FOUND K0 = %x  K1 = %x\n", k0, k1);
               // printf("\n");
                return 1;
        }
    }

    return 0;
}


int slideIt()
{
    int c, d;

    for(c = 0; c < 30; c++)
    {
        for(d = 0; d < 30; d++)
            if (c != d)
                 if (slidePair(plain[c], cipher[c], plain[d], cipher[d]))
                    return 1;
    }
    return 0;
}

int bruteIt()
{
    int c, d;

    for(c = 0; c <= 0xFF; c++)
        for(d = 0; d <= 0xFF; d++)
        {

                int crapped = 0;
                int e;
                for(e = 0; e < 10; e++)
                {
                    if (encrypt(plain[e], c, d) != cipher[e])
                    {
                        crapped = 1;
                        break;
                    }
                }
                if (crapped) continue;
                return 1;
        }
        return 0;
}

int main()
{
    srand(time(NULL));

    printf("Simple Slide Attack\n");

    int goodOnes = 0;
    int f;
    for(f = 0; f < 1000; f++)
    {
        realK0 = rand() & 0xFF;
        realK1 = rand() & 0xFF;

        int c;
        for(c = 0; c < 200; c++)
        {
            plain[c] = rand() & 0xFF;
            cipher[c] = encrypt(plain[c], realK0, realK1);
        }

        if (slideIt())
            goodOnes++;
    }

    printf("PERCENTAGE FOUND = %i\n", goodOnes * 100 / f);
    return 0;
}