asc.c

des加密算法源码

#include <stdio.h>
/*
extern static void cookey(unsigned long *, unsigned long *, int);
*/
int main()
{
	int i;
	unsigned long kn[32];
	unsigned long subkeys[32];

	for(i=0;i<32;i++)
	  kn[i]=0x11111111+i;

        cookey(subkeys, kn, 1);
	for(i=0;i<32;i++){
	  printf(" %x",subkeys[i]);
	  if(i%8==0) printf("\n");
	}

	printf("\n");

        cookey(subkeys, kn, 0);
	for(i=0;i<32;i++){
	  printf(" %x",subkeys[i]);
	  if(i%8==0) printf("\n");
	}

	printf("\n");

	return 0;
}

static void cookey(unsigned long *subkeys,unsigned long *kn,int encrypt)
{
	unsigned long *cooked, *raw0, *raw1;
	int increment;
	unsigned int i;

	raw1 = kn;
	cooked = encrypt ? subkeys : &subkeys[30];
	increment = encrypt ? 1 : -3;

	for (i = 0; i < 16; i++, raw1++) {
		raw0 = raw1++;
		*cooked    = (*raw0 & 0x00fc0000L) << 6;
		*cooked   |= (*raw0 & 0x00000fc0L) << 10;
		*cooked   |= (*raw1 & 0x00fc0000L) >> 10;
		*cooked++ |= (*raw1 & 0x00000fc0L) >> 6;
		*cooked    = (*raw0 & 0x0003f000L) << 12;
		*cooked   |= (*raw0 & 0x0000003fL) << 16;
		*cooked   |= (*raw1 & 0x0003f000L) >> 4;
		*cooked   |= (*raw1 & 0x0000003fL);
		cooked += increment;
	}
}