#include "stdafx.h"
#include "des.h"
#define usgc unsigned char

usgc Lmove[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
static  usgc IP[] = {
    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,
    56, 48, 40, 32, 24, 16,  8, 0,
    58, 50, 42, 34, 26, 18, 10, 2,
    60, 52, 44, 36, 28, 20, 12, 4,
    62, 54, 46, 38, 30, 22, 14, 6
};

static usgc IP_1[] = {
    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,
    32, 0, 40,  8, 48, 16, 56, 24
};

static usgc PC_1[] = {
    56, 48, 40, 32, 24, 16,  8,
     0, 57, 49, 41, 33, 25, 17,
     9,  1, 58, 50, 42, 34, 26,
    18, 10,  2, 59, 51, 43, 35,
    62, 54, 46, 38, 30, 22, 14,
     6, 61, 53, 45, 37, 29, 21,
    13,  5, 60, 52, 44, 36, 28,
    20, 12,  4, 27, 19, 11,  3
};

static usgc PC_2[] = {
    13, 16, 10, 23,  0,  4,
     2, 27, 14,  5, 20,  9,
    22, 18, 11,  3, 25,  7,
    15,  6, 26, 19, 12,  1,
    40, 51, 30, 36, 46, 54,
    29, 39, 50, 44, 32, 47,
    43, 48, 38, 55, 33, 52,
    45, 41, 49, 35, 28, 31
};

static usgc E[] = {
    31,  0,  1,  2,  3,  4,
     3,  4,  5,  6,  7,  8,
     7,  8,  9, 10, 11, 12,
    11, 12, 13, 14, 15, 16,
    15, 16, 17, 18, 19, 20,
    19, 20, 21, 22, 23, 24,
    23, 24, 25, 26, 27, 28,
    27, 28, 29, 30, 31,  0
};

static usgc P[] = {
    15,  6, 19, 20,
    28, 11, 27, 16,
     0, 14, 22, 25,
     4, 17, 30,  9,
     1,  7, 23, 13,
    31, 26,  2,  8,
    18, 12, 29,  5,
    21, 10,  3, 24
};

static usgc S[8][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,
};

usgc get2bit(usgc *ssd, int i)
{
    return (ssd[i>>3] & (usgc)(0x80>>(i&0x07))) != 0;
}

void set2bit(usgc *ssd, int i, usgc bit)
{
    usgc *cp, msk;
    cp = ssd + (i >> 3);
    msk = (usgc)(0x80>>(i&0x07));
    if (bit != 0)
        *cp = *cp | msk;
    else
        *cp = *cp & (~msk);
}

/* 字串位循環左移 */
void srol(int len, int bits, usgc *buf)
{
    int i;
    usgc tmp[8];
    memcpy(tmp, buf, 8);                        // 保留左邊bits位數據
    bits = bits % len;
    for (i=bits; i<len; i++)
        set2bit(buf, i-bits, get2bit(buf, i));  // 所有位左移bits位
    for (i=bits-1; i>=0; i--)
        set2bit(buf, len+i-bits, get2bit(tmp, i));   // 填補右邊位數
}

usgc loopk[16][8];
void mkkey(usgc *key)
{
    int i, j, k, t;
    usgc C[28], D[28];
    memset(loopk, 0, 16*8);
    for (i=0; i<28; i++) {
        C[i] = get2bit(key, PC_1[i]);
        D[i] = get2bit(key, PC_1[i+28]);
    }
    for (i=0, k=Lmove[i]; i<16; i++, k+=Lmove[i])
        for (j=0; j<24; j++) {
            set2bit(loopk[i], j, (usgc)((t=PC_2[j]+k) > 27 ? C[t-28]:C[t]));
            set2bit(loopk[i], j+24, (usgc)((t=PC_2[j+24]-28+k) > 27 ? D[t-28]:D[t]));
        }
}

usgc *DESFunc(usgc *key, usgc *ssd, int op)
{
    int i, j, k, r, x;
    usgc sch, Pi[8], mx[8], tmp[8], Pii[8];
    r = (op == 1) ? 0 : 15;
    mkkey(key);                                             /* 生成所有密鑰 */
    for (i=0; i<64; i++)
        set2bit(Pi, i, get2bit(ssd, IP[i]));                /* 明文IP變換 */
    for (i=0; i<16; i++) {
        for (j=0; j<48; j++)
            set2bit(Pii, j, (usgc)(get2bit(loopk[r], j) ^ get2bit(Pi, E[j]+32)));   // E變換
        for (j=0; j<8; j++) {
            sch = 0;
            x = j*6;
            for (k=0; k<6; k++)
                sch = (usgc)((sch<<1) | get2bit(Pii, x+k));
            x = (unsigned int)((sch&0x20) | ((sch&0x01)<<4) | (sch>>1)&0x0F);
            sch = S[j][x];                                  /* S替換 */
            for (k=0; k<4; k++)
                set2bit(mx, j*4+k, get2bit(&sch, k+4));
        }
        for (j=0; j<32; j++)
            set2bit(tmp, j, (usgc)(get2bit(Pi, j) ^ get2bit(mx, P[j]))); // P變換
        memcpy(Pi, Pi+4, 4);
        memcpy(Pi+4, tmp, 4);
        r = r + op;                                     /* 若是解密則r遞減 */
    }
    memcpy(tmp, Pi+4, 4);
    memcpy(tmp+4, Pi, 4);
    for (i=0; i<64; i++)
        set2bit(ssd, i, get2bit(tmp, IP_1[i]));          /* IP_1逆變換 */
    return ssd;
}

//密碼加密
char *EnCryptPin(char *key, char *src, char *dst)
{
	memcpy(dst, src, 8);
	DESFunc((usgc *)key, (usgc *)dst, 1);
	dst[8] = 0;
	return dst;
}

//密碼解密
char *DeCryptPin(char *key, char *src, char *dst)
{
	memcpy(dst, src, 8);
	DESFunc((usgc *)key, (usgc *)dst, -1);
	dst[8] = 0;
	return dst;
}