/*
    Provided by wangjunchuan, Northeastern University 
*/
#include <stdio.h>
#include <memory.h>
#include <string.h>

// 初始置換表
const static char IP_Table[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, 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
};

// 逆初始置換表
const static char IPR_Table[64] = {
	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
};

// 擴(kuò)展置換表
static const char Extension_Table[48] = {
	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
};

// P盒置換表
const static char P_Table[32] = {
	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
};

// 密鑰置換表 
const static char PCK_Table[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, 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
};

// 壓縮置換表 
const static char PCC_Table[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, 45, 33, 48,
	44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
};

// 每輪移動(dòng)的位數(shù) 
const static char LOOP_Table[16] = {
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

// S盒設(shè)計(jì)
const static char S_Box[8][4][16] = {
	// S盒1 
	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,
	// S盒2 
    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,
	// S盒3 
    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,
	// S盒4 
     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,
	// S盒5 
     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,
	// S盒6 
    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,
	// S盒7 
     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,
	// S盒8 
    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
};

typedef bool    (*PSubKey)[16][48];
enum    {ENCRYPT,DECRYPT};
static bool SubKey[2][16][48];// 16圈子密鑰
static bool Is3DES;// 3次DES標(biāo)志
static char Tmp[256], deskey[16];

/*
static void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type);//標(biāo)準(zhǔn)DES加/解密
static void SetKey(const char* Key, int len);// 設(shè)置密鑰
static void SetSubKey(PSubKey pSubKey, const char Key[8]);// 設(shè)置子密鑰
static void F_func(bool In[32], const bool Ki[48]);// f 函數(shù)
static void S_func(bool Out[32], const bool In[48]);// S 盒代替
static void Transform(bool *Out, bool *In, const char *Table, int len);// 變換
static void Xor(bool *InA, const bool *InB, int len);// 異或
static void RotateL(bool *In, int len, int loop);// 循環(huán)左移
static void ByteToBit(bool *Out, const char *In, int bits);// 字節(jié)組轉(zhuǎn)換成位組
static void BitToByte(char *Out, const bool *In, int bits);// 位組轉(zhuǎn)換成字節(jié)組


// Type—ENCRYPT:加密,DECRYPT:解密
// 輸出緩沖區(qū)(Out)的長(zhǎng)度 >= ((datalen+7)/8)*8,即比datalen大的且是8的倍數(shù)的最小正整數(shù)
// In 可以= Out,此時(shí)加/解密后將覆蓋輸入緩沖區(qū)(In)的內(nèi)容
// 當(dāng)keylen>8時(shí)系統(tǒng)自動(dòng)使用3次DES加/解密,否則使用標(biāo)準(zhǔn)DES加/解密.超過16字節(jié)后只取前16字節(jié)
bool DES_Act(char *Out,char *In,long datalen,const char *Key,int keylen,bool Type = ENCRYPT);
*/

// 字節(jié)轉(zhuǎn)換函數(shù)
void ByteToBit(bool *Out, const char *In, int bits)
{
    for(int i=0; i<bits; ++i)
        Out[i] = (In[i>>3]>>(i&7)) & 1;
}

// 比特轉(zhuǎn)換函數(shù)
void BitToByte(char *Out, const bool *In, int bits)
{
    memset(Out, 0, bits>>3);
    for(int i=0; i<bits; ++i)
        Out[i>>3] |= In[i]<<(i&7);
}

// 變換函數(shù)
void Transform(bool *Out, bool *In, const char *Table, int len)
{
    for(int i=0; i<len; ++i)
        Tmp[i] = In[ Table[i]-1 ];
    memcpy(Out, Tmp, len);
}

// 異或函數(shù)的實(shí)現(xiàn)
void Xor(bool *InA, const bool *InB, int len)
{
    for(int i=0; i<len; ++i)
        InA[i] ^= InB[i];
}

// 輪轉(zhuǎn)函數(shù)
void RotateL(bool *In, int len, int loop)
{
    memcpy(Tmp, In, loop);
    memcpy(In, In+loop, len-loop);
    memcpy(In+len-loop, Tmp, loop);
}

// S函數(shù)的實(shí)現(xiàn)
void S_func(bool Out[32], const bool In[48])
{
    for(char i=0,j,k; i<8; ++i,In+=6,Out+=4) {
        j = (In[0]<<1) + In[5];
        k = (In[1]<<3) + (In[2]<<2) + (In[3]<<1) + In[4];
		ByteToBit(Out, &S_Box[i][j][k], 4);
    }
}

// F函數(shù)的實(shí)現(xiàn)
void F_func(bool In[32], const bool Ki[48])
{
    static bool MR[48];
    Transform(MR, In, Extension_Table, 48);
    Xor(MR, Ki, 48);
    S_func(In, MR);
    Transform(In, In, P_Table, 32);
}



// 設(shè)置子密鑰
void SetSubKey(PSubKey pSubKey, const char Key[8])
{
    static bool K[64], *KL=&K[0], *KR=&K[28];
    ByteToBit(K, Key, 64); //轉(zhuǎn)換格式
    Transform(K, K, PCK_Table, 56); 
	// 由56位密鑰產(chǎn)生48位子密鑰
    for(int i=0; i<16; ++i) {
        RotateL(KL, 28, LOOP_Table[i]);
        RotateL(KR, 28, LOOP_Table[i]);
        Transform((*pSubKey)[i], K, PCC_Table, 48); 
    }
}


// 設(shè)置密鑰
void SetKey(const char* Key, int len)
{
	memset(deskey, 0, 16);
	memcpy(deskey, Key, len>16?16:len);
	SetSubKey(&SubKey[0], &deskey[0]);
	Is3DES = len>8 ? (SetSubKey(&SubKey[1], &deskey[8]), true) : false;
}

// DES加解密函數(shù)
void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type)
{
    static bool M[64], tmp[32], *Li=&M[0], *Ri=&M[32];
    ByteToBit(M, In, 64);
    Transform(M, M, IP_Table, 64);
    if( Type == ENCRYPT ){
        for(int i=0; i<16; ++i) {
            memcpy(tmp, Ri, 32);
            F_func(Ri, (*pSubKey)[i]); // 調(diào)用F函數(shù)
            Xor(Ri, Li, 32);
            memcpy(Li, tmp, 32);
        }
    }else{
        for(int i=15; i>=0; --i) {
            memcpy(tmp, Li, 32);
            F_func(Li, (*pSubKey)[i]);
            Xor(Li, Ri, 32);
            memcpy(Ri, tmp, 32);
        }
	}
    Transform(M, M, IPR_Table, 64);
    BitToByte(Out, M, 64);
}

// DES加解密函數(shù)（可以對(duì)長(zhǎng)明文分段加密）
bool DES_Act(char *Out, char *In, long datalen, const char *Key, int keylen, bool Type)
{
    if( !( Out && In && Key && (datalen=(datalen+7)&0xfffffff8) ) ) 
		return false;
	SetKey(Key, keylen);
	if( !Is3DES ) {   // 1次DES
		for(long i=0,j=datalen>>3; i<j; ++i,Out+=8,In+=8)
			DES(Out, In, &SubKey[0], Type);
	} else{   // 3次DES 加密:加(key0)-解(key1)-加(key0) 解密::解(key0)-加(key1)-解(key0)
		for(long i=0,j=datalen>>3; i<j; ++i,Out+=8,In+=8) {
			DES(Out, In,  &SubKey[0], Type);
			DES(Out, Out, &SubKey[1], !Type);
			DES(Out, Out, &SubKey[0], Type);
		}
	}
	return true;
}









void main()
{
	// 密鑰設(shè)置
	char key[]={0,2,1,0,9,4,5,1,7,8,5,0,7,2,8};
    // 設(shè)置明文
	char plain_text[]=" Welcome to DES world! It is wonderful! ";
	char encrypt_text[255]; // 密文
	char decrypt_text[255]; // 解密文

	memset(encrypt_text,0,sizeof(encrypt_text));
	memset(decrypt_text,0,sizeof(decrypt_text));

	printf("\nDES加密前的明文:\n");
	printf("%s\n\n",plain_text);

	
    // 進(jìn)行DES加密
	DES_Act(encrypt_text, plain_text, sizeof(plain_text), key, sizeof(key), ENCRYPT);
	printf("\nDES加密后的密文:\n");
	printf("%s\n\n",encrypt_text);

	DES_Act(decrypt_text, encrypt_text, sizeof(plain_text), key, sizeof(key), DECRYPT);
	printf("\n解密后的輸出:\n");
	printf("%s",decrypt_text);

	getchar();
}