des.c

包括BASE64编码的C语言实现,DES加密的C实现,共享内存,信号量的C实现

#include "des.h"
#include "stdio.h"
#include "memory.h"

/* initial permutation IP */
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
};

/* final permutation IP^-1 */
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
};

/* expansion operation matrix */
static const char e_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
};

/* 32-bit permutation function P used on the output of the S-boxes */
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
};

/* permuted choice table (key) */
const static char pc1_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
};

/* permuted choice key (table) */
const static char pc2_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
};

/* number left rotations of pc1 */
const static char loop_table[16] = {
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

/* The (in)famous S-boxes */
const static char s_box[8][4][16] = {
	/* S1 */ 
	{
		{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}
	},
	/* S2 */ 
	{
		{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}
	},
	/* S3 */
	{
		{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}
	},
	/* S4 */ 
	{
		{ 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}
 	},
	/* S5 */
	{
		{ 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}
	},
	/* S6 */ 
	{
		{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}
	},
	/* S7 */ 
	{
		{ 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}
	},
	/* S8 */ 
	{
		{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];

static void stddes(char ob[8], char ib[8], const psubkey psk, bool type);
static void setkey(const char *key, int len);
static void setsubkey(psubkey psk, const char key[8]);
static void f_func(bool ib[32], const bool ki[48]);
static void s_func(bool ob[32], const bool in[48]);
static void transform(bool *ob, bool *ib, const char *table, int len);
static void x_or(bool *in1, const bool *in2, int len);
static void rotatel(bool *ib, int len, int loop);
static void byte2bit(bool *ob, const char *ib, int bytes);
static void bit2byte(char *ob, const bool *ib, int bits);

static bool subkey[2][16][48];
static bool is3des;
static char tmp[256], deskey[16];

/* des encrypt */
bool des_encrypt(char *ib, int il, char *ob, int ol, char *key, int kl)
{
	long i=0;
	long j=0;

	if (ib == NULL || ob == NULL || key == NULL)
		return false;
	
	il = ((il+7)/8)*8;
	printf("key: %s kenlen: %d\n", key, kl);
	printf("ib:\n");
	printhex(ib, il);
	printf("ob:\n");
	printhex(ob, ol);
	j = il >> 3;
	setkey(key, kl);
	if (!is3des)
	{
		for(i=0; i<j; i++, ob+=8, ib+=8)
		{
			stddes(ob, ib, &subkey[0], true);
		}
	}
	else
	{
		for(i=0; i<j; i++, ob+=8, ib+=8)
		{
			stddes(ob, ib, &subkey[0], true);
			stddes(ob, ob, &subkey[1], false);
			stddes(ob, ob, &subkey[0], true);
		}
	}	

	return true;
}

/* des decrypt */
bool des_decrypt(char *ib, int il, char *ob, int ol, char *key, int kl)
{
	printf("key: %s keylen: %d\n", key, kl);
	printf("ib:\n");
	printhex(ib, il);
	
	printf("ob:\n");
	printhex(ob, ol);
	
	long i=0;
        long j=0;
                                                                                                                             
        if (ib == NULL || ob == NULL || key == NULL)
                return false;
                                                                                                                             
	il = ((il+7)/8)*8;
        j = il >> 3;
        setkey(key, kl);
        if (!is3des)
        {
                for(i=0; i<j; i++, ob+=8, ib+=8)
                {
                        stddes(ob, ib, &subkey[0], false);
                }
        }
        else
        {
                for(i=0; i<j; i++, ob+=8, ib+=8)
                {
                        stddes(ob, ib, &subkey[0], false);
                        stddes(ob, ob, &subkey[1], true);
                        stddes(ob, ob, &subkey[0], false);
                }
        }
                                                                                                                             
        return true;

}

/* set des key */
void setkey(const char *key, int len)
{
	memset(deskey, 0, sizeof(deskey));
	memcpy(deskey, key, len>16 ? 16 : len); 
	setsubkey(&subkey[0], &deskey[0]);
	if (len > 8)
	{
		setsubkey(&subkey[1], &deskey[8]);
		is3des = true;
	}
	else
		is3des = false;
	
}

/* std des */
void stddes(char ob[8], char ib[8], const psubkey psk, bool type)
{

        printf("ib:\n");
        printhex(ib, 8);

        printf("ob:\n");
        printhex(ob, 8);

	static bool m[64];
	static bool tmp[32];
	static bool *li = &m[0];
	static bool *ri = &m[32];

	byte2bit(m, ib, 64);
	transform(m, m, ip_table, 64);
	
	/* encrypt */
	if (type)
	{
		for(int i=0; i<16; i++)
		{
			memcpy(tmp, ri, 32);
			f_func(ri, (*psk)[i]);
			x_or(ri, li, 32);
			memcpy(li, tmp, 32);
		}
	}
	else
	{
		for(int i=15; i>=0; --i)
		{
			memcpy(tmp, li, 32);
			f_func(li, (*psk)[i]);
			x_or(li, ri, 32);
			memcpy(ri, tmp, 32);
		}
	}

	transform(m, m, ipr_table, 64);
	bit2byte(ob, m, 64);
}

/* set subkey */
void setsubkey(psubkey psk, const char key[8])
{
	static bool k[64];
	static bool *kl=&k[0];
	static bool *kr=&k[28];
	
	byte2bit(k, key, 64);
	transform(k, k, pc1_table, 56);
	for(int i=0; i<16; i++)
	{
		rotatel(kl, 28, loop_table[i]);
		rotatel(kr, 28, loop_table[i]);
		transform((*psk)[i], k, pc2_table, 48);
	}
}

/* f_function */
void f_func(bool ib[32], const bool ki[48])
{
	static bool mr[48];
	
	transform(mr, ib, e_table, 48);
	x_or(mr, ki, 48);
	s_func(ib, mr);
	transform(ib, ib, p_table, 32);
}

/* s_function */
void s_func(bool ob[32], const bool ib[48])
{
	char i=0;
	char j;
	char k;
	
	for(i=0; i<8; ++i, ib+=6, ob+=4)
	{
		j = (ib[0]<<1) + ib[5];
		k = (ib[1]<<3) + (ib[2]<<2) + (ib[3]<<1) + ib[4];
		byte2bit(ob, &s_box[i][j][k], 4);
	} 
}

/* transform */
void transform(bool *ob, bool *ib, const char *table, int len)
{
	for(int i=0; i<len; ++i)
	{
		tmp[i] = ib[table[i]-1];
	}

	memcpy(ob, tmp, len);
}

/* x_or */
void x_or(bool *ib1, const bool *ib2, int len)
{
	for(int i=0; i<len; ++i)
	{
		ib1[i] ^= ib2[i];
	}
}

/* rotate left */
void rotatel(bool *ib, int len, int loop)
{
	memcpy(tmp, ib, loop);
	memcpy(ib, ib+loop, len-loop);
	memcpy(ib+len-loop, tmp, loop); 
}

/* byte to bit */
void byte2bit(bool *ob, const char* ib, int bytes)
{
	for(int i=0; i<bytes; ++i)
	{
		ob[i] = (ib[i>>3]>>(i&7)) & 1;
	}
}

/* bit to byte */
void bit2byte(char *ob, const bool *ib, int bits)
{
	memset(ob, 0, bits>>3);
	for(int i=0; i<bits; i++)
	{
		ob[i>>3] |= ib[i] << (i&7);
	}
}

/* print with hex  */
void printhex(const char *s, int len)
{
	for(int i=0; i<len; i++)
	{
		printf("%08x ", s[i]);
		if ((i+1) % 10 == 0)
			printf("\n");
	}

	printf("\n");
}