des.cpp

加密算法DES的源码程序,有助于理解加密算法的过程.

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

#define UCHAR unsigned char

UCHAR C[17][28],D[17][28],K[17][48],c/*,ch*/;

int pc_1_c[28]={
	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
};
int pc_1_d[28]={
	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
};
int pc_2[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
};

int ls_count[16]={
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
int e_r[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
};

int P[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
};
int SSS[16][4][16]={
	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,/* err on */
	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, /* err on */

	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, /* err on */
	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
};
	
int ip_tab[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
};
int _ip_tab[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
};

void DES(UCHAR *key,UCHAR *text,UCHAR *mtext);
void _DES(UCHAR *key,UCHAR *text,UCHAR *mtext);
int _std_ansix98 ( char *pin_block , char *pan , char *passwd );
int std_ansix98 ( char *passwd , char *pan , char *pin_block );
void get_pan_part ( char *pan , char *part );
void disp_debug(UCHAR *buffer, int len);
UCHAR WriteFile(UCHAR *filename, UCHAR *buffer , int len, long position);
void InputZMK();
void InputZPK();
void EnPin();
void DePin();
void asc_to_bcd(UCHAR *bcd_buf, UCHAR *ascii_buf, int conv_len, UCHAR type);
void bcd_to_asc(UCHAR *ascii_buf, UCHAR *bcd_buf, int conv_len, UCHAR type);
void encrypt0(UCHAR *text, UCHAR *mtext);
void ip(UCHAR *text,UCHAR *ll,UCHAR *rr);
void _ip(UCHAR *text,UCHAR *ll,UCHAR *rr);
void F(int n,UCHAR *ll,UCHAR *rr,UCHAR *LL,UCHAR *RR);
void s_box(UCHAR *aa, UCHAR *bb);
void encrypt0(UCHAR *text, UCHAR *mtext);
void discrypt0(UCHAR *mtext,UCHAR *text);
void expand0(UCHAR *in, UCHAR *out);
void compress0(UCHAR *out, UCHAR *in);
void compress016(UCHAR *out,UCHAR *in);
void Decrypt();
void Encrypt();

struct KeyStr
{
	UCHAR zmk[9];
	UCHAR zpk[9];
};

struct KeyStr key;			

int main(void)
{
	UCHAR ch;
	FILE *fp;
	
	while(1)
	{
		clrscr();
		fflush(stdin);
		printf("1.设置主密钥\n");
		printf("2.设置工作密钥\n");
		printf("3.加密Pin\n");
		printf("4.解密Pin\n");
		printf("5.计算MAC值\n");
		printf("6.加密数据\n");
		printf("7.解密数据\n");
	
		fp = fopen("key_file.dat", "r+");
		if (fp == NULL)
			fp = fopen("key_file.dat", "w+");
		fread((UCHAR *)&key, sizeof(struct KeyStr), 1, fp);
		fclose(fp);
	
		ch = getch();
		switch(ch)
		{
		case '1':
			InputZMK();
			break;
		case '2':
			InputZPK();
			break;
		case '3':
			EnPin();
			break;
		case '4':
			DePin();
			break;
		case '5':
			//Mac();
			break;
		case '6':
			Encrypt();
			break;
		case '7':
			Decrypt();
			break;
		case '0':
			return 1;
		}
	}
}

void InputZMK()
{
    UCHAR buff[17];

	memset(buff, 0, sizeof(buff));
       	printf("\n    Input ZMK\n");
	bcd_to_asc(buff, key.zmk, 16, 0);
	printf("请输入ZMK: %s\n", buff);

	fflush(stdin);
	memset(buff, 0, sizeof(buff));
	scanf("%16s", buff);
	asc_to_bcd(key.zmk, buff, 16, 1);
	WriteFile("key_file.dat", (UCHAR *)&key, sizeof(struct KeyStr), 0);
	disp_debug(key.zmk, strlen(key.zmk));
}

void InputZPK()
{
    UCHAR buff[17];

	memset(buff, 0, sizeof(buff));
       	printf("\n   Input ZPK\n");
	bcd_to_asc(buff, key.zpk, 16, 0);
	printf("请输入ZPK: %s\n", buff);

	fflush(stdin);
	memset(buff, 0, sizeof(buff));
	scanf("%16s", buff);
	asc_to_bcd(key.zpk, buff, 16, 0);
	WriteFile("key_file.dat", (UCHAR *)&key, sizeof(struct KeyStr), 0);
	disp_debug(key.zpk, strlen(key.zpk));
}

void EnPin()
{
	UCHAR pinblk[17];
	UCHAR card[20], buff[17];
	UCHAR pwd[9];
	
	memset(pwd, 0, sizeof(pwd));
	memset(card, 0, sizeof(card));
	memset(buff, 0, sizeof(buff));
	memset(pinblk, 0, sizeof(pinblk));
	
       	printf("\n   Encrypt Pin\n");
	printf("请输入卡号:");
	fflush(stdin);
	scanf("%s", card);
	printf("请输入密码:");
	fflush(stdin);
	fflush(stdin);
	scanf("%6s", pwd);
	
	std_ansix98(pwd, card, pinblk);
	DES(key.zpk, pinblk, buff);
	disp_debug(buff, 8);
	memset(pinblk, 0, sizeof(pinblk));
	bcd_to_asc(pinblk, buff, 16, 0);
	disp_debug(pinblk, strlen(pinblk));
}

void DePin()
{
	UCHAR pinblk[17];
	UCHAR card[20], buff[17];
	UCHAR pwd[9];
	
	memset(pwd, 0, sizeof(pwd));
	memset(card, 0, sizeof(card));
	memset(buff, 0, sizeof(buff));
	memset(pinblk, 0, sizeof(pinblk));
	
       	printf("\n  Decrypt PIN\n");
	printf("请输入卡号:");
	fflush(stdin);
	scanf("%s", card);
	printf("请输入PinBlk:");
	fflush(stdin);
	scanf("%16s", buff);
	
	asc_to_bcd(pinblk, buff, 16, 1);
	_DES(key.zpk, pinblk, buff);
	_std_ansix98(buff,  card, pwd);
	memset(buff, 0, sizeof(buff));
	asc_to_bcd(buff, pwd, 6, 0);
	disp_debug(buff, 3);
}

void Encrypt()
{
	UCHAR buff[17];
	UCHAR Inbuff[100];
	
	memset(Inbuff, 0, sizeof(Inbuff));
	memset(buff, 0, sizeof(buff));
	
	printf("\n   Encrypt  \n");
	printf("请输入要加密的数据:");
	fflush(stdin);
	scanf("%100s", buff);

	asc_to_bcd(Inbuff, buff, 16, 0);
	memset(buff, 0, sizeof(buff));
	DES(key.zmk, Inbuff, buff);
	disp_debug(buff, strlen(buff));
	memcpy(Inbuff, buff, 8);
	bcd_to_asc(buff, Inbuff, 16, 0);
	disp_debug(buff, strlen(buff));
}

void Decrypt()
{
	UCHAR buff[17];
	UCHAR Inbuff[100];
	
	memset(Inbuff, 0, sizeof(Inbuff));
	memset(buff, 0, sizeof(buff));
	
	printf("\n   Decrypt  \n");
	printf("请输入要解密的数据:");
	fflush(stdin);
	scanf("%16s", buff);
	//asc_to_bcd(Inbuff, buff, 16, 0);
	memset(buff, 0, sizeof(buff));
	_DES(key.zmk, Inbuff, buff);
	disp_debug(buff, strlen(buff));
}

UCHAR WriteFile(UCHAR *filename, UCHAR *buffer , int len, long position)
{
	UCHAR rtn = 0;
	FILE *fp;

	if ((fp = fopen(filename, "r+")) == NULL)
	{
		if ((fp = fopen(filename, "w+")) == NULL)
		{
				rtn = 1;
				return rtn;
		}
	}
	position *= len;
	fseek(fp, position, SEEK_SET);
	fwrite((UCHAR *)buffer, len, 1, fp);
	fclose(fp);
	return rtn;
}

void disp_debug(UCHAR *buffer, int len)
{
	int i;

	printf("\nRESULT:");
	for(i=0; i<len; i++)
	{
		if ((i%25) == 0)
			printf("\n");
		printf("%02x ", buffer[i]);
	}
	getch();
	fflush(stdin);
}


void LS(unsigned char *bits,unsigned char *buffer,int count)
{
	int i;

	for (i=0;i<28;i++)
	{
		buffer[i]=bits[(i+count)%28];
	}
}

void son(UCHAR *cc,UCHAR *dd,UCHAR *kk)
{
	int i,j;
	unsigned char buffer[56];
	for (i=0;i<28;i++)
		buffer[i]=*cc++;

	for (i=28;i<56;i++)
		buffer[i]=*dd++;

	for (i=0;i<48;i++)
		*kk++=buffer[pc_2[i]-1];
}
	
void setkeystar(UCHAR *bits)
{
	int i,j;

	for (i=0;i<28;i++)
		C[0][i]=bits[pc_1_c[i]-1];
	for (i=0;i<28;i++)
		D[0][i]=bits[pc_1_d[i]-1];
	for (j=0;j<16;j++)
	{
		LS(C[j],C[j+1],ls_count[j]);
		LS(D[j],D[j+1],ls_count[j]);
		son(C[j+1],D[j+1],K[j+1]);
	}
}




void ip(UCHAR *text,UCHAR *ll,UCHAR *rr)
{
	int i,j;
	unsigned char buffer[64];
	unsigned char tmp[64];
	expand0(text,buffer);

	for (i=0;i<32;i++)
		ll[i]=buffer[ip_tab[i]-1];

	for (i=0;i<32;i++)
		rr[i]=buffer[ip_tab[i+32]-1];
}

void _ip(UCHAR *text,UCHAR *ll,UCHAR *rr)
{
	int i,j;
	unsigned char tmp[64];
	for (i=0;i<32;i++)
		tmp[i]=ll[i];
	for (i=32;i<64;i++)
		tmp[i]=rr[i-32];
	for (i=0;i<64;i++)
		text[i]=tmp[_ip_tab[i]-1];
}

void F(int n,UCHAR *ll,UCHAR *rr,UCHAR *LL,UCHAR *RR)
{
	int i,j;
	unsigned char buffer[64],tmp[64];
	for (i=0;i<48;i++)
		buffer[i]=rr[e_r[i]-1];
	for (i=0;i<48;i++)
		buffer[i]=(buffer[i]+K[n][i])&1;

	s_box(buffer,tmp);

	for (i=0;i<32;i++)
		buffer[i]=tmp[P[i]-1];

	for (i=0;i<32;i++)
		RR[i]=(buffer[i]+ll[i])&1;

	for (i=0;i<32;i++)
		LL[i]=rr[i];


}

void s_box(UCHAR *aa, UCHAR *bb)
{
	int i,j,k,m;
	int y,z;
	unsigned char ss[8];
	m=0;
	for (i=0;i<8;i++)
	{
		j=6*i;
		y=aa[j]*2+aa[j+5];
		z=aa[j+1]*8+aa[j+2]*4+aa[j+3]*2+aa[j+4];
		ss[i]=SSS[i][y][z];
		y=0x08;
		for (k=0;k<4;k++)
		{
			bb[m++]=(ss[i]/y)&1;
			y/=2;
		}

	}
}

void encrypt0(UCHAR *text, UCHAR *mtext)
{
	UCHAR ll[64],rr[64],LL[64],RR[64];
	UCHAR tmp[64];
	int i,j;
	ip(text,ll,rr);

	for (i=1;i<17;i++)
	{
		F(i,ll,rr,LL,RR);
		for (j=0;j<32;j++)
		{
			ll[j]=LL[j];
			rr[j]=RR[j];
		}
	}

	_ip(tmp,rr,ll);

	compress0(tmp,mtext);
}

void discrypt0(UCHAR *mtext,UCHAR *text)
{
	UCHAR ll[64],rr[64],LL[64],RR[64];
	UCHAR tmp[64];
	int i,j;
	ip(mtext,ll,rr);

	for (i=16;i>0;i--)
	{
		F(i,ll,rr,LL,RR);
		for (j=0;j<32;j++)
		{
			ll[j]=LL[j];
			rr[j]=RR[j];
		}
	}

	_ip(tmp,rr,ll);

	compress0(tmp,text);
}

void expand0(UCHAR *in, UCHAR *out)
{
	int divide;
	int i,j;

	for (i=0;i<8;i++)
	{
		divide=0x80;
		for (j=0;j<8;j++)
		{
			*out++=((in[i]/divide)&1);
			divide/=2;
		}
	}
}

void compress0(UCHAR *out, UCHAR *in)
{
	int times;
	int i,j;

	for (i=0;i<8;i++)
	{
		times=0x80;
		in[i]=0;
		for (j=0;j<8;j++)
		{
			in[i]+=(*out++)*times;
			times/=2;
		}
	}
}

void compress016(UCHAR *out,UCHAR *in)
{
	int times;
	int i,j;

	for (i=0;i<16;i++)
	{
		times=0x8;
		in[i]='0';
		for (j=0;j<4;j++)
		{
			in[i]+=(*out++)*times;
			times/=2;
		}
	}
}
void DES(UCHAR *key,UCHAR *text,UCHAR *mtext)
{
	UCHAR tmp[64];
	
	expand0(key,tmp);
	setkeystar(tmp);
	encrypt0(text,mtext);
}

void _DES(UCHAR *key,UCHAR *text,UCHAR *mtext)
{
	UCHAR tmp[64];
	
	expand0(key,tmp);
	setkeystar(tmp);
	discrypt0(text,mtext);
}
void asc_to_bcd(UCHAR *bcd_buf, UCHAR *ascii_buf, int conv_len, UCHAR type)
{
int    cnt;
char   ch, ch1;

 if (conv_len&0x01 && type ) ch1=0;
	else ch1=0x55;
 for (cnt=0; cnt<conv_len; ascii_buf++, cnt++) {
	if (*ascii_buf >= 'a' ) ch = *ascii_buf-'a' + 10;
	else if ( *ascii_buf >= 'A' ) ch =*ascii_buf- 'A' + 10;
	else if ( *ascii_buf >= '0' ) ch =*ascii_buf-'0';
	else ch = 0;
	if (ch1==0x55) ch1=ch;
	else {
	*bcd_buf++=ch1<<4 | ch;
	ch1=0x55;
	}
 }
 if (ch1!=0x55) *bcd_buf=ch1<<4;
}

void bcd_to_asc(UCHAR *ascii_buf, UCHAR *bcd_buf, int conv_len, UCHAR type)
{
    int cnt;

    if (conv_len&0x01 && type) {cnt=1; conv_len++;}
    else cnt=0;
    for (; cnt<conv_len; cnt++, ascii_buf++){
	*ascii_buf = ((cnt&0x01) ? (*bcd_buf++&0x0f) : (*bcd_buf>>4));
	*ascii_buf += ((*ascii_buf>9) ? ('A'-10) : '0');
    }
}

void get_pan_part ( char *pan , char *part )
{
	char	buf1[32];

	memset( buf1 , '0' , 4 );
	memcpy( buf1+4 , pan+strlen(pan)-13 , 12 );
	asc_to_bcd ( part , buf1 , 16 , 0 );
}

int _std_ansix98 ( char *pin_block , char *pan , char *passwd )
{
	char	buf1[32] , buf2[32];
	int	i;

	get_pan_part ( pan , buf1 );
	for ( i=0 ; i < 8 ; i++ )
	{
		buf2[i]=pin_block[i]^buf1[i];
	}

	if ( (buf2[0]&0x0ff) > 8 )
		return -1;
	bcd_to_asc ( passwd , buf2+1 , buf2[0]&0x0ff , 0 );

	passwd[buf2[0]&0x0ff] = '\0';

	return 0;
}

int std_ansix98 ( char *passwd , char *pan , char *pin_block )
{
	char	buf1[32] , buf2[32];
	int	i;

	get_pan_part ( pan , buf1 );

	buf2[0]=strlen(passwd)&0x0ff;

	memset ( buf2+1 , 0x0ff , 7 );

	asc_to_bcd ( buf2+1 , passwd , strlen(passwd) , 0 );
	
	for ( i=0 ; i < 8 ; i++ )
	{	
		pin_block[i]=buf1[i]^buf2[i];
	}
	
	return 0;
}