ECB-DES

main.c

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

void exor4(char *destination, const char *source1, const char *source2)
{
    *destination &= 0x0F;
    for (int i = 0; i < 4; i++)
        *destination |= (((*source1 >> (7 - i)) & 1) ^ ((*source2 >> (7 - i)) & 1)) << (7 - i);
    
}

void exor6(char *destination, const char *source1, const char *source2)
{
    *destination &= 0x03;
    for (int i = 0; i < 6; i++)
        *destination |= (((*source1 >> (7 - i)) & 1) ^ ((*source2 >> (7 - i)) & 1)) << (7 - i);
    
}

void execPermutation(char *destination, const char *source,
    int destinationBitSize, int destinationByteNum, int sourceByteNum, const int *v)
{
    char temp[sourceByteNum];
    memcpy(temp, source, sourceByteNum);
    memset(destination, 0, destinationByteNum);
    
    for (int i = 0; i < destinationByteNum; i++)
        for (int j = 0; j < 8; j++)
            if (i * 8 + j < destinationBitSize) {
                destination[i] |= ((temp[(v[i * 8 + j] - 1) / 8]
                    >> (7 - (v[i * 8 + j] - 1) % 8)) & 1) << (7 - j);
            }
    
}

void initialPermutation(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 64, 8, 8, v);
}

void finalPermutation(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 64, 8, 8, v);
}

void expansionFunction(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 48, 6, 4, v);
}

void permutation(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 32, 4, 4, v);
}

void permutedChoice1_Left(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 28, 4, 8, v);
}

void permutedChoice1_Right(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 28, 4, 8, v);
}

void permutedChoice2(char *destination, const char *source)
{
    int v[] = {
        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,
    };
    
    execPermutation(destination, source, 48, 6, 7, v);
}

void sBoxes(char *destination, const char *source)
{
    int v[][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,
        },
    };
    
    unsigned long long temp = 0;
    memcpy(&temp, source, 6);
    
    unsigned long tempDest = 0;
    memset(&tempDest, 0, 4);
    
    unsigned long long maskX = 0x7800000000000000;
    unsigned long long maskY = 0x8400000000000000;
    for (int i = 0; i < 8; i++) {
        tempDest |= v[i][(temp & maskX >> 23) + (temp & maskY >> 22) * 16] << (i * 4);
        temp <<= 6;
    }
    memcpy(destination, &tempDest, 4);
}

void keySchedule(char subkey[][6], const char *key)
{
    int r[] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
    unsigned long leftKey, rightKey;
    
    permutedChoice1_Left((char *)&leftKey, key);
    permutedChoice1_Right((char *)&rightKey, key);
    leftKey &= 0xFFFFFFF0;
    rightKey &= 0xFFFFFFF0;
    
    unsigned long temp = 0;
    for (int i = 0; i < 16; i++) {
        temp = ((leftKey <<= r[i]) << 28) | (rightKey <<= r[i]);
        permutedChoice2(subkey[i], (char *)&temp);
    }
}

void fiestel(char *destination, const char *source, const int round, const char *subkey)
{
    char temp[6];
    expansionFunction(temp, source);
    
    exor6(temp, subkey, temp);
    
    sBoxes(destination, temp);
    permutation(destination, destination);
}

void des(char *cipher, const char *plain, const char *key)
{
    char subkey[16][6];
    keySchedule(subkey, key);
    
    memcpy(cipher, plain, 8);
    initialPermutation(cipher, cipher);
    
    char temp[4];
    for (int i = 0; i < 15; i++) {
        memcpy(temp, cipher + 4, 4);
        fiestel(cipher + 4, cipher + 4, i, subkey[i]);
        exor4(cipher + 4, cipher, cipher + 4);
        memcpy(cipher, temp, 4);
    }
    memcpy(temp, cipher, 4);
    fiestel(cipher, cipher + 4, 15, subkey[15]);
    exor4(cipher, temp, cipher);
    
    finalPermutation(cipher, cipher);
}

int main()
{
    char *plainText = (char *)malloc(128 * sizeof(char));
    char *cipherText = (char *)malloc(128 * sizeof(char));
    
    fgets(plainText, 128, stdin);
    
    int blockNum = strlen(plainText) / 8 + 1;
    *(plainText + strlen(plainText)) = 1;
    
    for (int i = 0; i < blockNum; i++)
        des(cipherText + i * 8, plainText + i * 8, "12345678");
    
    for (int i = 0; i < blockNum; i++)
        for (int j = 0; j < 8; j++)
            printf("%d: %d %c\n", i * 8 + j, cipherText[i * 8 + j],
                cipherText[i * 8 + j]);
    
    return 0;
}