C#如何调用C语言实现的dll？

        [DllImport("des.dll", CharSet = CharSet.Auto)]

        private static extern void makekey(string aptr, string kptr);



        [DllImport("des.dll")]

        private static extern void deskey(string key, short edf);



        [DllImport("des.dll")]

        private static extern void des(string inblock, string outblock); 



        private string desEncrypt(string src, string key)

        {

            string dest = "", byKey = "";

             

            makekey(key, byKey);  

               

            deskey(byKey, 0);  

            

            des(src, dest);  

               

            return   dest;   

        }

static void D3des(from, into)	/* amateur theatrics */

unsigned char *from;			/* unsigned char[24] */

unsigned char *into;			/* unsigned char[24] */

{

	unsigned long swap, leftt[2], middl[2], right[2];



	scrunch(from, leftt);

	scrunch(&from[8], middl);

	scrunch(&from[16], right);

	desfunc(leftt, KnL);

	desfunc(middl, KnL);

	desfunc(right, KnL);

	swap = leftt[1];

	leftt[1] = middl[0];

	middl[0] = swap;

	swap = middl[1];

	middl[1] = right[0];

	right[0] = swap;

	desfunc(leftt, KnR);

	desfunc(middl, KnR);

	desfunc(right, KnR);

	swap = leftt[1];

	leftt[1] = middl[0];

	middl[0] = swap;

	swap = middl[1];

	middl[1] = right[0];

	right[0] = swap;

	desfunc(leftt, Kn3);

	desfunc(middl, Kn3);

	desfunc(right, Kn3);

	unscrun(leftt, into);

	unscrun(middl, &into[8]);

	unscrun(right, &into[16]);

	return;

	}



void make3key(aptr, kptr)

register char *aptr;				/* NULL-terminated   */

register unsigned char *kptr;		/* unsigned char[24] */

{

	register unsigned char *store;

	register int first, i;

	unsigned long savek[96];



	cp3key(savek);

	des3key(Df_Key, DES_EN0);

	for( i = 0; i < 24; i++ ) kptr[i] = Df_Key[i];

	first = 1;

	while( (*aptr != '\0') || first ) {

		store = kptr;

		for( i = 0; i < 24 && (*aptr != '\0'); i++ ) {

			*store++ ^= *aptr & 0x7f;

			*aptr++ = '\0';

			}

		D3des(kptr, kptr);

		first = 0;

		}

	use3key(savek);

	return;

	}



#endif	/* D3_DES */

#endif	/* D2_DES */



/* Validation sets:

 *

 * Single-length key, single-length plaintext -

 * Key	  : 0123 4567 89ab cdef

 * Plain  : 0123 4567 89ab cde7

 * Cipher : c957 4425 6a5e d31d

 *

 * Double-length key, single-length plaintext -

 * Key	  : 0123 4567 89ab cdef fedc ba98 7654 3210

 * Plain  : 0123 4567 89ab cde7

 * Cipher : 7f1d 0a77 826b 8aff

 *

 * Double-length key, double-length plaintext -

 * Key	  : 0123 4567 89ab cdef fedc ba98 7654 3210

 * Plain  : 0123 4567 89ab cdef 0123 4567 89ab cdff

 * Cipher : 27a0 8440 406a df60 278f 47cf 42d6 15d7

 *

 * Triple-length key, single-length plaintext -

 * Key	  : 0123 4567 89ab cdef fedc ba98 7654 3210 89ab cdef 0123 4567

 * Plain  : 0123 4567 89ab cde7

 * Cipher : de0b 7c06 ae5e 0ed5

 *

 * Triple-length key, double-length plaintext -

 * Key	  : 0123 4567 89ab cdef fedc ba98 7654 3210 89ab cdef 0123 4567

 * Plain  : 0123 4567 89ab cdef 0123 4567 89ab cdff

 * Cipher : ad0d 1b30 ac17 cf07 0ed1 1c63 81e4 4de5

 *

 * d3des V5.0a rwo 9208.07 18:44 Graven Imagery

 **********************************************************************/

static void desfunc(block, keys)

register unsigned long *block, *keys;

{

	register unsigned long fval, work, right, leftt;

	register int round;



	leftt = block[0];

	right = block[1];

	work = ((leftt >> 4) ^ right) & 0x0f0f0f0fL;

	right ^= work;

	leftt ^= (work << 4);

	work = ((leftt >> 16) ^ right) & 0x0000ffffL;

	right ^= work;

	leftt ^= (work << 16);

	work = ((right >> 2) ^ leftt) & 0x33333333L;

	leftt ^= work;

	right ^= (work << 2);

	work = ((right >> 8) ^ leftt) & 0x00ff00ffL;

	leftt ^= work;

	right ^= (work << 8);

	right = ((right << 1) | ((right >> 31) & 1L)) & 0xffffffffL;

	work = (leftt ^ right) & 0xaaaaaaaaL;

	leftt ^= work;

	right ^= work;

	leftt = ((leftt << 1) | ((leftt >> 31) & 1L)) & 0xffffffffL;



	for( round = 0; round < 8; round++ ) {

		work  = (right << 28) | (right >> 4);

		work ^= *keys++;

		fval  = SP7[ work		 & 0x3fL];

		fval |= SP5[(work >>  8) & 0x3fL];

		fval |= SP3[(work >> 16) & 0x3fL];

		fval |= SP1[(work >> 24) & 0x3fL];

		work  = right ^ *keys++;

		fval |= SP8[ work		 & 0x3fL];

		fval |= SP6[(work >>  8) & 0x3fL];

		fval |= SP4[(work >> 16) & 0x3fL];

		fval |= SP2[(work >> 24) & 0x3fL];

		leftt ^= fval;

		work  = (leftt << 28) | (leftt >> 4);

		work ^= *keys++;

		fval  = SP7[ work		 & 0x3fL];

		fval |= SP5[(work >>  8) & 0x3fL];

		fval |= SP3[(work >> 16) & 0x3fL];

		fval |= SP1[(work >> 24) & 0x3fL];

		work  = leftt ^ *keys++;

		fval |= SP8[ work		 & 0x3fL];

		fval |= SP6[(work >>  8) & 0x3fL];

		fval |= SP4[(work >> 16) & 0x3fL];

		fval |= SP2[(work >> 24) & 0x3fL];

		right ^= fval;

		}



	right = (right << 31) | (right >> 1);

	work = (leftt ^ right) & 0xaaaaaaaaL;

	leftt ^= work;

	right ^= work;

	leftt = (leftt << 31) | (leftt >> 1);

	work = ((leftt >> 8) ^ right) & 0x00ff00ffL;

	right ^= work;

	leftt ^= (work << 8);

	work = ((leftt >> 2) ^ right) & 0x33333333L;

	right ^= work;

	leftt ^= (work << 2);

	work = ((right >> 16) ^ leftt) & 0x0000ffffL;

	leftt ^= work;

	right ^= (work << 16);

	work = ((right >> 4) ^ leftt) & 0x0f0f0f0fL;

	leftt ^= work;

	right ^= (work << 4);

	*block++ = right;

	*block = leftt;

	return;

	}



#ifdef D2_DES



void des2key(hexkey, mode)		/* stomps on Kn3 too */

unsigned char *hexkey;			/* unsigned char[16] */

short mode;

{

	short revmod;



	revmod = (mode == DES_EN0) ? DES_DE1 : DES_EN0;

	deskey(&hexkey[8], revmod);

	cpkey(KnR);

	deskey(hexkey, mode);

	cpkey(Kn3);					/* Kn3 = KnL */

	return;

	}



void Ddes(from, into)

unsigned char *from, *into;		/* unsigned char[8] */

{

	unsigned long work[2];



	scrunch(from, work);

	desfunc(work, KnL);

	desfunc(work, KnR);

	desfunc(work, Kn3);

	unscrun(work, into);

	return;

	}



void D2des(from, into)

unsigned char *from;			/* unsigned char[16] */

unsigned char *into;			/* unsigned char[16] */

{

	unsigned long *right, *l1, swap;

	unsigned long leftt[2], bufR[2];



	right = bufR;

	l1 = &leftt[1];

	scrunch(from, leftt);

	scrunch(&from[8], right);

	desfunc(leftt, KnL);

	desfunc(right, KnL);

	swap = *l1;

	*l1 = *right;

	*right = swap;

	desfunc(leftt, KnR);

	desfunc(right, KnR);

	swap = *l1;

	*l1 = *right;

	*right = swap;

	desfunc(leftt, Kn3);

	desfunc(right, Kn3);

	unscrun(leftt, into);

	unscrun(right, &into[8]);

	return;

	}



void makekey(aptr, kptr)

register char *aptr;				/* NULL-terminated  */

register unsigned char *kptr;		/* unsigned char[8] */

{

	register unsigned char *store;

	register int first, i;

	unsigned long savek[96];



	cpDkey(savek);

	des2key(Df_Key, DES_EN0);

	for( i = 0; i < 8; i++ ) kptr[i] = Df_Key[i];

	first = 1;

	while( (*aptr != '\0') || first ) {

		store = kptr;

		for( i = 0; i < 8 && (*aptr != '\0'); i++ ) {

			*store++ ^= *aptr & 0x7f;

			*aptr++ = '\0';

			}

		Ddes(kptr, kptr);

		first = 0;

		}

	useDkey(savek);

	return;

	}



void make2key(aptr, kptr)

register char *aptr;				/* NULL-terminated   */

register unsigned char *kptr;		/* unsigned char[16] */

{

	register unsigned char *store;

	register int first, i;

	unsigned long savek[96];



	cpDkey(savek);

	des2key(Df_Key, DES_EN0);

	for( i = 0; i < 16; i++ ) kptr[i] = Df_Key[i];

	first = 1;

	while( (*aptr != '\0') || first ) {

		store = kptr;

		for( i = 0; i < 16 && (*aptr != '\0'); i++ ) {

			*store++ ^= *aptr & 0x7f;

			*aptr++ = '\0';

			}

		D2des(kptr, kptr);

		first = 0;

		}

	useDkey(savek);

	return;

	}



#ifndef D3_DES	/* D2_DES only */

#ifdef	D2_DES	/* iff D2_DES! */



void cp2key(into)

register unsigned long *into;	/* unsigned long[64] */

{

	register unsigned long *from, *endp;



	cpkey(into);

	into = &into[32];

	from = KnR, endp = &KnR[32];

	while( from < endp ) *into++ = *from++;

	return;

	}



void use2key(from)				/* stomps on Kn3 too */

register unsigned long *from;	/* unsigned long[64] */

{

	register unsigned long *to, *endp;



	usekey(from);

	from = &from[32];

	to = KnR, endp = &KnR[32];

	while( to < endp ) *to++ = *from++;

	cpkey(Kn3);					/* Kn3 = KnL */

	return;

	}



#endif	/* iff D2_DES */

#else	/* D3_DES too */



static void D3des(unsigned char *, unsigned char *);



void des3key(hexkey, mode)

unsigned char *hexkey;			/* unsigned char[24] */

short mode;

{

	unsigned char *first, *third;

	short revmod;



	if( mode == DES_EN0 ) {

		revmod = DES_DE1;

		first = hexkey;

		third = &hexkey[16];

		}

	else {

		revmod = DES_EN0;

		first = &hexkey[16];

		third = hexkey;

		}

	deskey(&hexkey[8], revmod);

	cpkey(KnR);

	deskey(third, mode);

	cpkey(Kn3);

	deskey(first, mode);

	return;

	}



void cp3key(into)

register unsigned long *into;	/* unsigned long[96] */

{

	register unsigned long *from, *endp;



	cpkey(into);

	into = &into[32];

	from = KnR, endp = &KnR[32];

	while( from < endp ) *into++ = *from++;

	from = Kn3, endp = &Kn3[32];

	while( from < endp ) *into++ = *from++;

	return;

	}



void use3key(from)

register unsigned long *from;	/* unsigned long[96] */

{

	register unsigned long *to, *endp;



	usekey(from);

	from = &from[32];

	to = KnR, endp = &KnR[32];

	while( to < endp ) *to++ = *from++;

	to = Kn3, endp = &Kn3[32];

	while( to < endp ) *to++ = *from++;

	return;

	}